- Plan B: California Braces for Climate Change
- What Cuba Can Teach Us About Health Care
- Gene Grows Worm Heads
- See Better by Believing You Can
- Twin Study Deepens Multiple Sclerosis Mystery
- Ice Discovered on Asteroid, Suggests Earth’s Oceans Came From Space
- Feathered Dinosaurs Molted Like Birds
- Semi-Natural Biotech Hack Makes Bones Heal 3 Times Faster
- High Metabolism Fueled Evolution of Bat Flight
- EPA Scientist Says East Coast Beaches Threatened by Sea Level, But Nobody’s Listening
Posted: 29 Apr 2010 01:07 PM PDT
When it comes to environmental regulation, California doesn't wait for the Feds to ride in and lay down the law. The Golden State led the way on mandating emissions-control equipment in motor vehicles in 1961. It pioneered tailpipe-emissions standards in 1967 and ratcheted them up into the 1990s, prompting the federal government to follow. When the Environmental Protection Agency proved reluctant to tighten fuel-economy standards, California outmaneuvered it in 2002 by limiting carbon dioxide from cars. That decision achieved the same end — and was the first move in the United States to control greenhouse gases.
And so it goes with climate change. By the mid-2000s, when the rest of the country was waking up to the challenge of global warming, California was already pursing an aggressive program to assess the likely damage. According to the state energy commission's climate research, the U.S. west coast faces sea-level rise of 12 to 18 inches by 2050, and as much as nearly six feet by the turn of the century. Precipitation is projected to fall increasingly as water rather than snow, draining into the sea rather than lying in cold storage until the long, dry summers. Higher-than-average temperatures and more frequent extreme weather promise heat waves, wildfires, droughts and floods.
The sense of impending crisis sent California Governor Arnold Schwarzenegger into action-hero mode. In 2006, he signed the Global Warming Solutions Act, capping carbon emissions statewide throughout all activities and sectors. Then, last December, he stood on Treasure Island — an expanse of landfill in the San Francisco Bay that stands to be inundated by the upwelling of glacial melt — and unveiled the 2009 California Climate Adaptation Strategy, a plan to prepare for what many scientists regard as inevitable changes. "We have the responsibility to have a Plan B just in case we can't stop the global warming," he said, apparently missing the document's emphatic assertion that mitigation (making efforts to minimize the onset of climate change) and adaptation (learning to live with it) are equally necessary and inherently complementary undertakings.
The strategy document is 200 pages of meticulously footnoted, thoroughly bureaucratic prose that directs state agencies to take climate change into account. Individual chapters are devoted to seven critical sectors: agriculture, biodiversity, coastal resources, energy and transportation, forestry, public health, and water supply and flood protection. The plan outlines the range and severity of potential impacts — eroding coastlines, flooded freeways, extended wildfire seasons, devastating disease outbreaks. The executive summary lists a dozen action items and an appendix of 163 further recommendations.
Mostly, these directives call for better coordination between federal, state and local regulators; updating existing resource-management plans in light of the latest scientific findings; ongoing research to sharpen estimates of impending change; and funding to accomplish these aims and, presumably, the more concrete actions that would follow. Perhaps most interesting is the recommendation to create a website called CalAdapt that would mash up government data with Google maps, providing officials with up-to-date visualizations of rising waters, increasing temperatures and other risks.
Not all of this is new. California's coastal and water agencies have been planning for the impact of climate change since the mid-1980s. Until the turn of the century, though, adaptation was a dirty word in Sacramento. "You got slapped on the head if you mentioned it," says Anthony Brunello, who worked for the Pew Center for Global Climate Change from 1999 to 2001. "It equated to giving up."
But evidence began to mount that the effects were already being felt, particularly a 7-inch rise in sea level at the Golden Gate over the past century, which convinced even hard-core advocates of mitigation that it wasn't too early to consider, say, building sea walls. In late 2008, Schwarzenegger ordered the California Natural Resources Agency to look into what it would take to adapt to the changes wrought by global warming.
By then, Brunello had become California's Deputy Secretary for Climate Change and Energy — and the state was deep into a fiscal crisis. He directed state agencies to form sector-specific working groups that invited business leaders, academics and NGOs to help hash out the strategy. The governor released the plan just in time for the Copenhagen climate summit — only to see it swept off the front pages when leaked e-mails from eminent climate scientists sparked the Climategate scandal.
That was a pity because — lack of bold proposals notwithstanding — the Climate Adaptation Strategy is a significant step forward in the U.S. response to climate change. "Of the dozen states published or working on plans that include adaptation measures, California stands out for the breadth and depth," says Terri Cruce, a climate researcher with the Pew Center for Global Climate Change and the Georgetown Climate Center. (Cruce maintains a website detailing climate-change adaptation initiatives on a state-by-state basis.) The report covers every state agency and reaches into every vital sector that's touched by climate change. Most important, it establishes a permanent task force to guide implementation, so the effort won't die when Schwarzenegger leaves office. And although it may seem trendy, the CalAdapt website looks like an especially smart move, creating a convenient, cost-effective way for officials see how latest projections play out in their jurisdiction.
Which is not to say the document is perfect. "It's a strategy, not a plan," Cruce notes — a set of general directions, not a detailed roadmap. Generally, action items are divided between politically low-cost/low-impact maneuvers (such as adding agricultural inspection stations to catch pests following warmer temperatures northward) and more ambitious goals (a host of measures to restore wetlands that would absorb storm surges) with no deadline, budget or process attached.
The milquetoast language of many recommendations ("Consider requiring applicants to address how sea-level rise will affect their project….") leaves officials with any number of ways to avoid taking action. Moreover, economic analysis is almost entirely absent. Given that both adaptation and mitigation will have a price tag, it's impossible to know which is more expensive in any given case. Is it more costly to cut emissions or relocate San Francisco International Airport on higher ground? And where will the money come from?
The strategy's harshest critics believe that such flaws render it ineffectual. Susanne Moser, a geographer who worked as a consultant on the project, dismisses the near-term goals as merely "best practices" and the long-term objectives as unattainable without a more forceful mandate. But she finds some good in the effort. The most important outcome, she says, isn't the document itself but a cultural shift in Sacramento: The disparate agencies, accustomed to competing for jurisdiction and funding, have discovered the value of cooperation. "They realized they needed to work together if they were going to get beyond business as usual," she says. "That's a huge shift — from 'I don't want to talk to these people' to 'let's work together.' It will make all the difference moving forward."
Despite weaknesses in the plan, most observers view it as an important first step. "There's a broad range of decision makers," says Matt Vander Sluis, who contributed to the effort as global warming program manager at the Planning and Conservation League, an environmental lobbying group based in Sacramento. "Some get it, but others need this type of guidance to wrap their heads around the problem." One immediate result, he points out, is that officials will think twice about approving proposed San Francisco Bay Area developments that would stand below sea level. "It's a useful set of recommendations," he says. "Now, state and federal decision makers need to make the investment in carrying them out, because without resources, it's going to be like trying to put out a fire without a fire hose."
The follow-up is already underway, starting with the top-line directive: formation of a task force to establish future priorities. William Reilly, who served as the first President Bush's head of the Environmental Protection Agency, leads the group, which is due to report its recommendations to the governor by summer. Meanwhile, the strategy will be updated every two years. By the time the first biennial review rolls around in late 2011, the short-term goals should be complete and presumably the roadmap to the more politically challenging recommendations will have been sketched in. That is, unless California finds that adapting to the new politics of climate change even harder than responding to the change itself.
This report was produced by the Climate Desk collaboration.
Image: The central San Francisco Bay coastline has areas, including the San Francisco International Airport, that will be inundated by a 16-inch sea-level rise (in light blue) and a 55-inch sea-level rise (in dark blue)./San Francisco Bay Conservation and Development Commission.
Ted Greenwald is a writer and editor in Northern California.
Posted: 29 Apr 2010 10:55 AM PDT
Just a morning's boat ride from the tip of Florida is a place where medical costs are low and doctors plentiful. It's Cuba, and Stanford University physician Paul Drain says it's time for the United States to pay attention to our neighbor's shoestring success.
Despite a 50-year trade embargo by the United States and a post-Soviet collapse in international support, the impoverished nation has developed a world-class health care system. Average life expectancy is 77.5 years, compared to 78.1 years in the United States, and infant and child mortality rates match or beat our own. There's one doctor for every 170 people, more than twice the per-capita U.S. average.
Not everything is perfect in Cuba. There are shortages of medicines, and the best care is reserved for elites. But it's still a powerful feat. "In Cuba, a little over $300 per person is spent on health care each year. In the U.S., we're spending over $7,000 per person," said Drain, co-author of Caring for the World and an essay published April 29 in Science. "They're able to achieve great health outcomes on a modest budget."
With Fidel Castro's reign as Cuba's leader ending two years ago, relations with the United States have thawed. President Obama eased restrictions on travel to Cuba last year, and the oft-introduced Free Trade With Cuba Act finally has a chance of passing Congress. Drain would like the Institutes of Medicine to conduct a full study of the island nation's success.
"There are so many lessons we might be able to learn from Cuba's health care and medical education system, but we don't know too much about it," said Drain.
Wired.com: How does Cuba keep health care costs so low?
Paul Drain: Partly by keeping physicians' salaries low. Obviously, given the government they have, they can do that. But they also emphasize primary care and preventive care, addressing diseases and problems before they become major. It's a very different approach to health care.
In the United States, we essentially do the opposite. We treat diseases when they occur. We're not very good at the preventive component, which causes the costs of our health system to be much higher.
Wired.com: What are the origins of Cuba's approach?
Drain: Starting in 1964, they encouraged all medical school graduates to do at least two years of service in a rural area. That program became so popular that by the mid-1970s, almost all new physicians were doing rural service. From there, almost all medical graduates were channeled into a three-year family medicine residency. That's where they do clinical training, making the transition to full doctor from medical student.
Almost all their residents do family medicine. They focus on primary care for all ages. Once everybody learns primary care, about 35 percent go on and specialize. It's quite the opposite of what we have here.
Wired.com: How so?
Drain: Our medical students choose what they want to do. Only about 7 or 8 percent go into family medicine, which is our primary care system. In Cuba, everyone becomes a primary care doctor. They learn to prevent diseases.
Cuba also provides very good access. In the mid-1980s, they created a system of neighborhood doctors' clinics. One doctor is responsible for a catchment area of a couple of city blocks. They get to know their patients well. If somebody has a problem, they can see the doctor in the clinic that day.
Wired.com: Could the U.S. government ever mandate a system like that?
Drain: It would be a big leap, but there are smaller steps that could be taken. We're the only developed country without universal access to a nationalized health care system. Other countries have seen health care as a basic right and insured everybody. Everyone gets primary care. That would be a first step.
I saw someone in my clinic yesterday who hadn't seen a doctor in 10 years. Her blood pressure was through the roof, and it's probably been like that for a decade. She's at tremendous risk for having a stroke or heart problems. If she'd seen somebody back when this started, it could have been controlled. But because of her high blood pressure, who knows what her future medical bills will be like.
If she were in the Cuban system, she would have had a visit scheduled yearly for the last 10 years. If she hadn't shown up, someone would have gone to her home to see if she was OK. Blood pressure is an easy thing to check. It would have been controlled.
Wired.com: One problem in the United States is the shortage of doctors. How does Cuba train physicians?
Drain: Education is paid by the government, so students don't have debt. In the United States, medical students come out $200,000 or $300,000 in the hole, which deters them from going into primary care. Cuban doctors are making a fraction of what we make in the U.S., but most Cubans aren't going into medicine to earn money. They're going into it to treat people in their communities.
In 1999, Cuba created a school of medicine for Latin America. They bring students in, train them for six years, give them room and board and a stipend. Afterward the students are required to go home and practice in poorer communities. It's a remarkable program, with 10,000 students now from 33 countries, and an interesting model for developing health care workers.
Wired.com: Do President Obama's health reforms move the United States toward what's seen in Cuba?
Drain: What we're passing is starting to move us in a better direction. I'm an advocate for universal health care, and there's still a long way to go. But I think we'll eventually catch up to our western counterparts, and realize that we're the only country not providing full equity in terms of accessing health care, and that's reflected in health outcomes. When you compare us against most developed countries, we're near the bottom in most health indicators. Our life expectancy isn't as good, our infant mortality rates are higher, and we're spending twice as much money.
Image: Cuba and the southern tip of Florida./NASA.
Citation: "Fifty Years of U.S. Embargo: Cuba's Health Outcomes and Lessons." By Paul K. Drain and Michele Barry. Science, Vol. 328 No. 5977, April 30, 2010.
Posted: 29 Apr 2010 10:13 AM PDT
A worm named Schmidtea mediterranea has the unique ability to regenerate not only its limbs, but also its head and brain. Now, scientists studying the worm have discovered one of the genes that allows it to accomplish this amazing feat.
The gene, called "smed-prep," regulates the location and structure of the flatworm's brain during regeneration. When the gene is absent, the worm forms a stump with random junk from other parts of its body, but no brain. When it's expressed in other areas of the body, heads can be made to sprout from anywhere.
"One of the main goals in the lab was to understand the mechanisms that allowed this worm to regenerate its head, brain and sensory organs," said molecular biologist Aziz Aboobaker of the University of Nottingham, lead author of the paper published in PLoS Genetics April 22. "It's a big problem because you have to make this all from the old tissue. The cells have to mobilize, migrate to the right place and differentiate."
The S. med worm is small, but has complex organs and a primitive bilateral brain. Not only can it regenerate its head and brain, but each piece you cut off (down to about 1 millimeter) can re-grow into a complete organism. The worm can do this because about 25 percent of its cells are stem cells, which can differentiate into any cell type.
To find the gene, Aboobaker scanned the worm's genome looking for developmental genes. After testing several other genes, Aboobaker's team stumbled upon smed-prep, whose expression was concentrated in the worm's head region.
To see how the gene affected the worm's ability to regenerate, they tricked the cell into destroying any messenger RNA or protein made from it, using interfering RNA. The worms who had their gene expression cut down were unable to regenerate their brains after amputation, but other aspects of the regeneration process were unaffected.
"That's the interesting thing, we haven't killed them off, they are still healthy," Aboobaker said. "They just can't navigate or find food."
Humans have a gene that is similar in biochemical structure and genetic code to smed-prep, but its function in humans is unknown. Related genes in other vertebrates, like mice and zebrafish, are expressed in the brain during embryo formation.
"The most interesting aspect of this paper is its evolutionary perspective," said cell biologist Alejandro Sánchez Alvarado, of the University of Utah, because C. elegans (a commonly studied worm) and drosophila (the fruitfly) do not appear to have evolved a directly corresponding gene. Alvarado previously discovered two other genes involved with S. med's head regeneration process.
The worm and its properties can teach us more about human health, because it's a good model system to learn about stem cells, regeneration and aging, said Aboobaker.
"You can't just make neurons from stem cells, then insert them into your brain, because you have no idea what would happen," he said. "If you ask someone to make you a brain from a ball of tissue, they won't be able to, because we don't know how. But the worm does."
The team's next step is to determine what other genes are regulated when smed-prep is turned on and off."Finding [smed-prep] means you can find which genes don't turn on properly when it is knocked down," Aboobaker said. "Those are the genes that must be involved in this network that makes the brain."
Image: Wikimedia Commons/Alejandro64
Citation: "The TALE Class Homeobox Protein Smed-prep Defines the Anterior Compartment for Head Regeneration." By Daniel A. Felix and A. Aziz Aboobaker. PLoS Genetics Vol. 6, Issue 4, April 22, 2010.
Posted: 29 Apr 2010 10:04 AM PDT
Imagine seeing better by thinking differently. That's a vision with a future, according to Harvard University psychologist Ellen Langer.
Eyesight markedly improved when people were experimentally induced to believe that they could see especially well, Langer and her colleagues report in the April Psychological Science. Such expectations actually enhanced visual clarity, rather than simply making volunteers more alert or motivated to focus on objects, they assert.
Langer's new findings build on long-standing evidence that visual perception depends not just on relaying information from the eyes to the brain but on experience-based assumptions about what can be seen in particular situations. Those expectations lead people to devote limited attention to familiar scenes and, as a result, to ignore unusual objects and events.
In perhaps the most eye-popping of Langer's new findings, 20 men and women who saw a reversed eye chart — arranged so that letters became progressively larger further down the chart, with a giant "E" at the bottom — accurately reported more letters from the smallest two lines than they did when shown a traditional eye chart with the big letters on top. All volunteers had normal eyesight.
These results reflect people's expectation, based on experience with standard eye charts, that letters are easy to see at the top and become increasingly difficult to distinguish on lower lines, the researchers suggest.
Participants who said they thought that they could improve their eyesight with practice displayed a bigger vision boost on the reversed chart than those who didn't think improvement was possible, but only for the next-to-smallest line. Both groups did equally well at reading the smallest, topmost line.
Another set of experiments included 63 members of the Reserve Officers' Training Corps at MIT. Eye testing determined that their vision ranged from below average to excellent.
An experimenter told a group of 22 cadets to assume the role of a fighter pilot while operating a flight simulator. During this exercise, participants tried to identify letters shown on four plane wings of approaching aircraft. Each wing contained one of the bottom four lines of an eye chart.
Another 20 cadets performed the visual task while pretending to fly a plane in a simulator that they were told was broken. Ten other cadets read a motivational essay before the exercise. A final group of 11 cadets didn't use a simulator but practiced eye exercises that researchers described as capable of improving eyesight before taking an eye test.
Vision improved substantially for nine of 22 simulator pilots compared with none of those who pretended to fly, two of 11 eye exercisers and one person in the motivational group. Simulator pilots did so well relative to the others because they more thoroughly adopted a mind-set of being real fighter pilots with presumably superior vision, the researchers posit. An initial survey of ROTC members found that they attributed particularly good vision to fighter pilots.
Simulator pilots with below-average vision displayed the biggest jumps in visual performance, perhaps because they had more room for improvement, the researchers suggest.
These results suggest that if eye exercise programs designed to improve vision work for some people, it's not because of any physical effect on the eyes or brain. Such regimens "may be effective because they prime the belief that exercise improves vision," Langer and her colleagues write.
Mind-set may boost visual performance without sharpening vision itself, comments psychologist Daniel Simons of the University of Illinois at Urbana-Champaign. Experimental manipulations in the new study, such as reversing the arrangement of an eye chart, may have made volunteers more willing to guess when they felt a bit unsure, Simons says. Such guesses stand a good chance of being right, in his view.
Posted: 28 Apr 2010 02:28 PM PDT
The most detailed genetic investigation ever of multiple sclerosis has produced more questions than answers.
Using extremely fine-grained analytical tools, scientists compared genetic information in three sets of identical twins. One of each pair had MS, and the other didn't — yet their genes proved essentially identical.
"We find no smoking gun on the genetic level," said National Center for Genome Resources geneticist Stephen Kingsmore, co-author of the study published April 28 in Nature.
The research cost $1.5 million, and the scientists took 18 months to sequence 2.8 billion DNA units in each twin, and determine whether they came from the mother or father. Most genomic comparisons look for differences in a just handful of suspect genes, and even whole-genome approaches don't differentiate between parental contributions.
The researchers also analyzed the twins' CD4 cells, a type of white blood cell that plays a central role in the development of MS. In these cells, the researchers sequenced epigenomes — chemical instructions that turn genes on and off — and transcriptomes, or a chemical record of genes that are actively coding proteins.
These multiple layers of information represent the cutting edge of genomic analysis, and are expected to reveal what rougher tools cannot. "This was a technical tour de force, and potentially represents a new way of looking at disease states," said Kingsmore. Nevertheless, they found no differences.
The absence of genetic differences doesn't mean that genetics are irrelevant to multiple sclerosis. Identical twins, who are descended from the same egg, are six times more likely to develop MS than non-identical twins, who come from two different eggs.
It's still possible that some as-yet-unknown genetic factor, undetectable by even the most advanced tools, may explain the discordance in the study. However, Kingsmore thinks the culprit is probably an unknown environmental influence. "There must be a nongenetic factor, probably environmental," that combines with known genetic and environmental risks, he said.
The researchers would like to look at more twins, and other types of cells. Even so, the study "was a pioneering effort on a scale that hasn't been done before," said Kingsmore. "We're left with this mystery."
Image: Combination of cover image of the current issue of Nature and transcriptome readings from the study./Nature
Citation: "Genome, epigenome and RNA sequences of monozygotic twins discordant for multiple sclerosis." By Sergio E. Baranzini, Joann Mudge, Jennifer C. van Velkinburgh, Pouya Khankhanian, Irina Khrebtukova, Neil A. Miller, Lu Zhang, Andrew D. Farmer, Callum J. Bell, Ryan W. Kim, Gregory D. May, Jimmy E. Woodward, Stacy J. Caillier, Joseph P. McElroy, Refujia Gomez, Marcelo J. Pando, Leonda E. Clendenen, Elena E. Ganusova, Faye D. Schilkey, Thiruvarangan Ramaraj, Omar A. Khan, Jim J. Huntley, Shujun Luo, Pui-yan Kwok, Thomas D. Wu, Gary P. Schroth, Jorge R. Oksenberg, Stephen L. Hauser, & Stephen F. Kingsmore. Nature, Vol. 464 No. 7293, April 29, 2010.
Posted: 28 Apr 2010 01:50 PM PDT
Water ice and organic molecules have been discovered on the surface of an asteroid for the first time.
Researchers glimpsed the ice on 24 Themis, the largest member of an asteroid family located between the orbits of Mars and Jupiter, using the NASA Infrared Telescope on Mauna Kea in Hawaii. This frosty little rock could be the key to understanding how Earth became the blue planet.
"What we've found suggests that an asteroid like this one may have hit Earth and brought our planet its water," said astronomer Humberto Campins of the University of Central Florida, the lead of one of the two separate teams that reported similar findings April 28 in Nature.
While there is plenty of debate around how Earth got its oceans, this new evidence suggests some of the water came from extraterrestrial sources. Here's how it may have happened: More than four billion years ago, after a massive collision between Earth and another large object created the moon, our planet was completely dessicated. Then, during the Late Heavy Bombardment period that followed, during which lots of asteroids hit Earth, the ice that the objects carried became our store of water.
"The more we find in our asteroid belt objects that do have water, the more convinced we are that that was a possible process to rehydrate the earth," said NASA astrobiologist Mary Voytek.
The ice on Themis 24 could be a sort of time capsule from the early solar system and could be similar to the ice that may have arrived on Earth from asteroids during the Heavy Bombardment.
"The ice that we see there, right now, is sort of related to the ice that could have come from the main asteroid belt that hit us about 4 billion years ago," astronomer Henry Hsieh of Queen's University Belfast told NPR. "It gives us a way to kind of probe the cousins of the asteroids that hit us and probably gave us water in the early stages of the Earth's formation." Hsieh wrote a commentary that accompanied the stories in Nature.
The presence of ice and organic molecules on the surface of an asteroid is the latest in a string of discoveries that collectively indicate water ice is a more common substance than we might have thought. In just the past few years, scientists have confirmed the presence of ice at the moon's north pole as well as beneath the surface of Mars.
It had previously been thought that asteroids were too warm to retain water ice on their surfaces. The exact method for how they do so remains unclear.
Image: Artist's conception of asteroid 24 Themis and two small fragments of this dynamic family, which resulted from a large impact more than one billion years ago. One of the small fragments is inert (as most asteroids are), and the other has a comet-like tail, produced by the sublimation of water ice from its surface.
Posted: 28 Apr 2010 10:30 AM PDT
Like kids today who don't want to dress like Mom and Dad, some young feathered dinosaurs sported a look totally unlike their elders, a new study shows.
The finding hints that feathered dinosaurs, like modern birds, molted as they grew, says study coauthor Xing Xu, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.
The dramatic age-related shift in plumage was noted in newly described fossils of Similicaudipteryx, a feathered creature that lived in what is now China about 125 million years ago. Xu and his colleagues analyzed two well preserved specimens of Similicaudipteyrx and report their findings in the April 29 Nature.
Both fossils are thought to come from juveniles, because the vertebrae aren't completely fused, which happens as animals reach adulthood, Xu says. In the larger and presumably older of the two specimens — a creature with an upper leg bone about 12 centimeters long and a body the size of a goose — the long feathers on the forelimbs and tail look just like modern bird feathers.
But in the pigeon-sized smaller creature, feathers on the forelimb and tail look modern only near their tips, Xu says. Closer to the body, those feathers have a ribbonlike shape but no central shaft — a type of structure previously seen in the tail feathers of some other Chinese feathered dinosaurs.
Unlike today's birds, these dinosaurs changed the basic structure of their feathers some time during adolescence, says Xu, probably due to different timing and patterns of gene activity.
Image: The strikingly different flight feathers of two individuals at different ontogenetic stages of the oviraptorosaurian Similicaudipteryx./Xing Lida and Song Qijin.
Posted: 28 Apr 2010 10:05 AM PDT
Mice healed three times faster than normal after their broken bones were flooded by proteins naturally used to regrow new tissues. The discovery raises the possibility of a stem cell–free route to regeneration.
The Wnt family of proteins used in the mice are involved in healing many other types of tissue; the researchers hope they will find many other uses for them.
"Gut, skin, brain, muscle, cardiac muscle, corneas, retinas — people have studied the role of Wnt signals in all those tissues," said Stanford University reconstructive surgeon and study co-author Jill Helms. "Maybe there could be a therapeutic approach to all this."
The experiment, published April 28 in Science Translational Medicine, is rooted in two decades of research on Wnt genes and proteins, which play a variety of regenerative roles. They help embryonic stem cells make copies of themselves, keeping a body's supply fresh, and guide the maturation of stem cells into specific cell types.
Wnt proteins are found throughout the animal kingdom, from sponges and flatworms to mice and humans, and their function seems to be consistent. When tissues are injured, Wnt genes in surrounding cells become more active, pumping out extra Wnt proteins. Arriving repair cells divide faster and grow more rapidly.
Study co-author Roel Nusse, a cell biologist at Stanford, has pioneered much of the Wnt research. He was responsible for cloning the Wnt family genes, allowing proteins to be produced in tissue cultures in a lab. His success encouraged the study's other authors to see if the proteins could be used therapeutically.
"This pathway may be the key to regenerating, or at least rapidly repairing, tissues," said Helms. "We're augmenting nature's own response to injury."
The researchers started their tests by genetically engineering a strain of mice that produced exceptionally high amounts of Wnt proteins. Three days after their bones were broken, they grew three and half times more new bone tissue than regular mice.
That test's purpose wasn't to investigate a role for genetic engineering, but rather to see if extra Wnt had an effect. The researchers next injected lab-grown Wnt proteins into mice with broken bones. These again healed three times faster.
There were no obvious side effects from the treatment, though the tests were preliminary. Somewhat disturbingly, Wnt genes were originally identified while malfunctioning in cancerous cells. The likelihood of causing cancer is also a major obstacle to developing safe stem cell therapies. But Helms is confident that it won't be a problem with potential Wnt therapies.
"In cancer, mutations cause the pathway to be always on. Delivering the protein only causes the pathway to be turned on for a moment," she said. "Mutations in the insulin pathway also cause cancer, but insulin treatments do not."
According to Thomas Einhorn, a Boston University biochemist and orthopedic surgeon who wasn't involved in the study, Wnt is an alluring therapeutic target. Malfunctions in Wnt regulation have been linked to human bone disorders, underscoring their importance. But he cautioned that "animal studies are animal studies, and human conditions are something else."
In mice, challenges still remain. A broken bone is relatively easy to target with an injection, but many conditions are less localized, involving entire organs or large amounts of tissue.
The researchers are now conducing mouse tests of Wnt proteins for skin wounds, stroke and heart-attack recovery, and cartilage injuries.
"Nature uses this recipe over and over again," said Helms.
Image: Healing in the skeletal tissues of mice given a placebo (top) and Wnt proteins (bottom).
Citation: "Wnt Proteins Promote Bone Regeneration." By S. Minear, P. Leucht, J. Jiang, B. Liu, Y. A. Zeng, C. Fuerer, R. Nusse, J. A. Helms. Science Translational Medicine, Vol. 2 No. 29, April 28, 2010.
Posted: 27 Apr 2010 11:49 AM PDT
From wings to low-density bones to echolocation, the evolution of flight in bats required many radical changes. But the most important change may have been metabolic.
A genetic comparison of dozens of mammal species shows that bats possess highly modified versions of genes responsible for turning food into energy. Improved energy efficiency would have encouraged their ancestors to move from treetop gliding, like modern flying squirrels, to actively flapping their arms.
"Gliding doesn't require huge amounts of energy, but when you start flapping your arms, you start needing more," said David Irwin, a University of Toronto evolutionary biologist. "Changes in energy synthesis need to get well underway before you get sustained flight."
The bat evolution study, published April 26 in the Proceedings of the National Academy of Sciences, grew from lead author Ya-Ping Zhang's interest in avian energy metabolism. In an earlier comparison of flightless and flying birds, the Chinese Academy of Sciences zoologist found that flightless birds had fewer genetic changes in their mitochondria — the cellular structures that turn oxygen and nutrients into chemical energy. Zhang wondered if mitochondria and flight were tightly linked in mammals, too.
The researchers analyzed mitochondrial genes from four species of bats and 60 other mammal species. By comparing the differences against known evolutionary histories, they extrapolated what mitochondria in a last common ancestor might have looked like.
When they compared modern bat mitochondria to the ancestral animal, they found profound changes in a subset of genes that code for enzymes that break down nutrients — the fuel cells of the fuel cells, so to speak. In bats, up to 23 percent of these genes show signs of adaptations. Just 2 percent of other genes have changed.
Because bats were fully formed by the time they appear in the fossil record, scientists don't know which adaptations came first. But Irwin thinks the mitochondrial changes must have come early, and are most important. To support their airborne lifestyle, bats require three to five times more energy than other mammals their size.
Irwin next hopes to study the physical structure of enzymes produced by bat mitochondria, with the aim of discovering exactly what makes them so efficient. The insights might eventually be applied to metabolic disorders like obesity and diabetes. "Maybe this will give us a better understanding of how to make our own energy system more efficient," Irwin said.
Citation: "Adaptive evolution of energy metabolism genes and the origin of ﬂight in bats ." By Yong-Yi Shen, Lu Liang, Zhou-Hai Zhu, Wei-Ping Zhou, David M. Irwin and Ya-Ping Zhang. Proceedings of the National Academy of Sciences, Vol. 107. No. 17, April 27, 2010.
Posted: 27 Apr 2010 11:26 AM PDT
For most of the 20th century, Chesapeake Beach, Maryland, was known for its boardwalk, amusement park and wide, sandy beaches, popular with daytrippers from Washington, D.C. "The bathing beach has a frontage of three miles," boasted a tourist brochure from about 1900, "and is equal, if not superior, to any beach on the Atlantic Coast."
Today, on a cloudless spring afternoon, the resort town's sweeping view of Chesapeake Bay is no less stunning. But there's no longer any beach in Chesapeake Beach. Where there once was sand, water now laps against a seven-foot-high wall of boulders protecting a strip of pricey homes marked with "No Trespassing" signs.
Surveying the armored shoreline, Jim Titus explains how the natural sinking of the shoreline and slow but steady sea-level rise, mostly due to climate change, have driven the bay's water more than a foot higher over the past century. Reinforcing the eroding shore with a sea wall held the water back, but it also choked off the natural supply of sand that had replenished the beach. What sand remained gradually sank beneath the rising water.
Titus, the Environmental Protection Agency's resident expert on sea-level rise, first happened upon Maryland's disappearing beaches 15 years ago while looking for a place to windsurf. "Having the name beach," he discovered, "is not a very good predictor of having a beach." Since then, he's kept an eye out for other beach towns that have lost their namesakes—Maryland's Masons Beach and Tolchester Beach, North Carolina's Pamlico Beach, and many more. (See a map of Maryland's phantom beach towns here.) A 54-year old with a thick shock of hair and sturdy build, Titus could pass for a vacationer in his Panama hat, khakis and polo shirt. But as he picks his way over the rocky shore, he's anything but relaxed.
For nearly 30 years, Titus has been sounding the alarm about our rising oceans. Global warming is melting polar ice, adding to the volume of the oceans, as well as warming up seawater, causing it to expand. Most climatologists expect oceans around the world to rise between 1.5 and 5 feet this century. Some of the hardest-hit areas could be in our own backyard: Erosion and a shift in ocean currents could cause water to rise 4 feet or more along much of the East Coast. Titus, who contributed to the Intergovernmental Panel on Climate Change's Nobel Prize-winning 2007 report, has done more than anyone to determine how those rising seas will affect us and what can be done about them.
Like his occasional collaborator, NASA climatologist James Hansen, Titus has decided to speak out. He's crisscrossed the country to meet with state and local officials in coastal areas, urging them to start planning now for the slow-motion flood. Yet his warnings have mostly fallen on deaf ears. "We were often told by midlevel officials that their bosses did not want to plan for anything past the next election," he says.
Neither, it seems, does the federal government. Over the past decade, Titus and a team of contractors combined reams of data to construct a remarkably detailed model of how sea-level rise will impact the eastern seaboard. It was the largest such study ever undertaken, and its findings were alarming: Over the next 90 years, 1,000 square miles of inhabited land on the east coast could be flooded, and most of the wetlands between Massachusetts and Florida could be lost. The favorably peer-reviewed study was scheduled for publication in early 2008 as part of a Bush Administration report on sea-level rise, but it never saw the light of day — an omission criticized by the EPA's own scientific advisory committee. Titus has urged the more science-friendly Obama administration to publish his work, but so far, it hasn't — and won't say why.
So Titus recently launched a personal website, risingsea.net, to publish his work. "I decided to do my best to prevent the taxpayer investment from being wasted," he says. The site includes "When the North Pole Melts," a prescient holiday ditty recorded by his musical alter ego, Captain Sea Level, in the late '80s.
Titus gazes at Chesapeake Beach's jagged shoreline, where two children scramble over the barrier of large gray boulders known as a revetment. "The children of 21st-century Chesapeake Beach, what do they do?" he asks. "They play on revetments." A generation ago, these kids might have been skipping through the waves. A generation from now, many of the rocks they're playing on will almost certainly be underwater.
Living near the ocean has always come with the risk of getting wet. Yet coastal dwellers whose homes got swamped by the occasional storm surge could rely on the water to eventually recede. That certainty is gone. Titus has calculated that a 3-foot rise in sea level will push back East Coast shorelines an average of 300 to 600 feet in the next 90 years, threatening to submerge densely developed areas inhabited by some 3 million people, including large parts of New York City, Philadelphia, and Washington, D.C. As Margaret Davidson, director of the National Oceanic and Atmospheric Administration's Coastal Services Center in Charleston, South Carolina, puts it, "Today's flood is tomorrow's high tide."
The rising waters can be kept at bay by constructing dikes and bulkheads, pumping sand to fill out receding beaches, and elevating existing buildings and roads on embankments or pylons. But such efforts may prove prohibitively expensive: Titus says that in the lower 48 states alone, they could cost as much as $1 trillion over the next century. He estimates that in the process, 60 to 90 percent of the east coast's wetlands could be destroyed as bulkheads and other defensive measures restrict the movement of estuaries and marshes, drowning them when the ocean rises.
So are developers getting ready for the water? The National Association of Home Builders, the housing industry's largest trade group, has no policy on adapting coastal projects to account for rising sea levels. "While sea-level rise may be a real issue in some areas," Susan Asmus, NAHB's senior vice president of regulatory and environmental affairs, told me in an e-mail, "it is but one of many considerations that are likely already taken into account during the planning process." Mother Jones contacted the nation's 10 largest homebuilders, including D.R. Horton, Pulte Homes, and Lennar. None would say how they are responding to sea-level rise.
Nor is there any evidence that the issue has much traction with homeowners — and why should it? Property insurance is readily available in most coastal areas, if not through private insurers, then through state governments and FEMA's National Flood Insurance Program. Though the NFIP requires policyholders to live above the 100-year high-water mark, it doesn't account for how that line may creep inland in the future. Besides, most people would plan to resell their beach houses long before they expect them to be swallowed by encroaching waves.
What about government? Most coastal states have done little or nothing to regulate shoreline development, often from fear of litigation. In 1988, South Carolina's Beachfront Management Act required new beach homes to be set back far enough from the water to be protected from at least 40 years of erosion. A property owner named David Lucas sued, and the U.S. Supreme Court eventually ruled that the construction ban had deprived him of any "economically viable use" of his coastal properties, a "taking" that required the state to compensate him. "After Lucas, fewer people spoke seriously about stopping development," Titus says.
A few state and local governments have taken more constructive action. Several states limit development near tidal waters (Maine and Rhode Island have done this specifically in response to sea-level rise). Chatham, Massachusetts, cites sea-level rise as one reason why it prohibits new homes, even elevated ones, below 100-year flood lines. (State courts have upheld those limits in Chatham and Maine because they still allow property to be used for recreation, farming, and other profitable activities.) In California, where erosion and winter storms routinely knock multimillion-dollar homes off seaside cliffs, the state's Coastal Commission has long required anyone who builds on coastal bluffs to submit a geotechnical report proving that their home won't fall into the ocean. Three years ago, it began requiring the reports to account for sea-level rise. And in a groundbreaking 2008 executive order, Governor Arnold Schwarzenegger directed state agencies to plan for sea-level rise in their construction projects.
A handful of developers have also started to seriously grapple with sea-level rise. A residential high-rise project on Treasure Island, a former naval base in San Francisco Bay, is being built far from the shoreline and is reserving funds for a protective berm if the water rises even higher than the 3 feet that's anticipated. And in the wake of Hurricane Katrina, the insurance industry drew up standards to fortify houses for stronger hurricanes and higher waves. So far, though, only 200 houses nationwide have been built to comply with the standards.
Most coastal dwellers are focused on riding out the next surge, not the next century. You can't really blame them — nobody really wants to hear that their days on the beach are numbered.
Case in point: Beyoncé's dad. Matthew Knowles has been locked in a bitter struggle to save his beach house in Galveston, Texas, which now sits on top of the high-tide line thanks to Hurricane Ike. In most states, Knowles would be allowed to shore up his home, but not in Texas, which is known for one of the most progressive laws in the country on beach access. The state's Open Beaches Act provides that beach is a public resource that must be protected from "erosion or reduction caused by development."
Last year, after Knowles started reinforcing his property with tons of cement, the Texas General Land Office informed him that paving over the beach is illegal. Even so, he continued and then surrounded his home with sod, planters, and sandbags. In March, the agency notified Knowles that it was preparing to fine him up to $2,000 a day for violating the Texas Open Beaches Act by interfering with "the right of the public to use the beach." Knowles did not respond to a request for comment.
Historically, the 51-year-old law has been used to prevent property owners from walling off the beach in front of their homes. But officials say the law clearly applies even when the beach comes to the houses, rather than vice versa. "Even if you make $80 million a year, we don't care," says Jim Suydam, a spokesman for the Texas General Land Office. "The beach is the public's." Incorporated into the state constitution last year and vigorously supported by the state's conservative, gun-packing land commissioner, the Open Beaches Act is remarkably popular, in part because it can guarantee beach access for ATVs.
Titus views the Texas Open Beaches Act as one of the more promising tools for preparing for higher water. It has unintended environmental benefits, ensuring that beaches can migrate inland instead of being walled off and at the same time, it sidesteps any debate over climate change. "Developers who deny that the sea will rise would view the policy as costing them nothing," because it wouldn't prevent them from building near the shore, he notes. Only the diehard beach dwellers would stand to get soaked.
Kate Sheppard contributed to this report.
Image: Elevations of land close to sea level in upper Chesapeake Bay. Elevations are above spring water, which is the average high tide during the new and full moons, and approximately the inland boundary of tidal wetlands.
Josh Harkinson is a staff reporter at Mother Jones, and Kate Sheppard covers energy and environmental politics in Mother Jones' Washington bureau.
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