The Largest Organism on Earth Is a Fungus

Strange but True: The Largest Organism on Earth Is a Fungus

The blue whale is big, but nowhere near as huge as a sprawling fungus in eastern Oregon 
 

	Image: USDA FOREST SERVICE, PACIFIC NORTHWEST RESEARCH STATION
	HIDDEN GIANT:  A small outcropping of honey mushrooms on the surface hide the largest known organism on Earth, a fungus infesting the woods of eastern Oregon.

Next time you purchase white button mushrooms at the grocery store, just remember, they may be cute and bite-size but they have a relative out west that occupies some 2,384 acres (965 hectares) of soil in Oregon's Blue Mountains. Put another way, this humongous fungus would encompass 1,665 football fields, or nearly four square miles (10 square kilometers) of turf.

The discovery of this giant Armillaria ostoyae in 1998 heralded a new record holder for the title of the world's largest known organism, believed by most to be the 110-foot- (33.5-meter-) long, 200-ton blue whale. Based on its current growth rate, the fungus is estimated to be 2,400 years old but could be as ancient as 8,650 years, which would earn it a place among the oldest living organisms as well.

A team of forestry scientists discovered the giant after setting out to map the population of this pathogenic fungus in eastern Oregon. The team paired fungal samples in petri dishes to see if they fused (see photo below), a sign that they were from the same genetic individual, and used DNA fingerprinting to determine where one individual fungus ended.

This one, A. ostoyae, causes Armillaria root disease, which kills swaths of conifers in many parts of the U.S. and Canada. The fungus primarily grows along tree roots via hyphae, fine filaments that mat together and excrete digestive enzymes. But Armillaria has the unique ability to extend rhizomorphs, flat shoestringlike structures, that bridge gaps between food sources and expand the fungus's sweeping perimeter ever more.

A combination of good genes and a stable environment has allowed this particularly ginormous fungus to continue its creeping existence over the past millennia. "These are very strange organisms to our anthropocentric way of thinking," says biochemist Myron Smith of Carleton University in Ottawa, Ontario. An Armillaria individual consists of a network of hyphae, he explains. "Collectively, this network is called the mycelium and is of an indefinite shape and size."

All fungi in the Armillaria genus are known as honey mushrooms, for the yellow-capped and sweet fruiting bodies they produce. Some varieties share this penchant for monstrosity but are more benign in nature. In fact the very first massive fungus discovered in 1992—a 37-acre (15-hectare) Armillaria bulbosa, which was later renamed Armillaria gallica—is annually celebrated at a "fungus fest" in the nearby town of Crystal Falls, Mich.

Image: USDA FOREST SERVICE, PACIFIC NORTHWEST RESEARCH STATION
GENETIC TEST:  By pairing samples in a petri dish and seeing if they grow together scientists can tell if widely separated fungi are actually the same individual.

Myron Smith was a PhD candidate in botany at the University of Toronto when he and colleagues discovered this exclusive fungus in the hardwood forests near Crystal Falls. "This was kind of a side project," Smith recalls. "We were looking at the boundaries of [fungal] individuals using genetic tests and the first year we didn't find the edge."

Next, the microbiologists developed a new way to tell an individual apart from a group of closely related siblings using a battery of molecular genetic techniques. The major test compared fungal genes for telltale signs of inbreeding, where heterozygous strips of DNA become homozygous. That's when they realized they had struck it big. The individual Armillaria bulbosa they found weighed over 100 tons (90.7 metric tons) and was roughly 1,500 years old.

"People had ideas that maybe they were big but nobody had any idea they were that big," says Tom Volk, a biology professor at the University of Wisconsin–La Crosse. "Well it's certainly the biggest publicity that mycology is going to get—maybe ever."

Soon afterward, the discovery of an even bigger fungus in southwestern Washington was announced by Terry Shaw, then in Colorado with the U.S. Forest Service (USFS), and Ken Russell, a forest pathologist at Washington State Department of Natural Resources, in 1992. Their fungus, a specimen of Armillaria ostoyae, covered about 1,500 acres (600 hectares) or 2.5 square miles (6.5 square kilometers). And in 2003 Catherine Parks of the USFS in Oregon and her colleagues published their discovery of the current behemoth 2,384-acre Armillaria ostoyae.

Ironically, the discovery of such huge fungi specimens rekindled the debate of what constitutes an individual organism. "It's one set of genetically identical cells that are in communication with one another that have a sort of common purpose or at least can coordinate themselves to do something," Volk explains.

Both the giant blue whale and the humongous fungus fit comfortably within this definition. So does the 6,615-ton (six-million-kilogram) colony of a male quaking aspen tree and his clones that covers 107 acres (43 hectares) of a Utah mountainside.

And, at second glance, even those button mushrooms aren't so tiny. A large mushroom farm can produce as much as one million pounds (454 metric tons) of them in a year. "The mushrooms that people grow in the mushroom houses&133;; they're nearly genetically identical from one grower to another," Smith says. "So in a large mushroom-growing facility that would be a genetic individual—and it's massive!"  

In fact, humongous may be in the nature of things for a fungus. "We think that these things are not very rare," Volk says. "We think that they're in fact normal."

 

Ozone hole has shrunk by nearly a third: European Space Agency

Ozone hole has shrunk by nearly a third: European Space Agency

The ozone hole over Antarctica shrank by 30 percent this year compared with the record loss recorded in 2006, the European Space Agency (ESA) said on Wednesday.

Measurements made by the agency's Envisat satellite found a peak loss in the ozone layer of 27.7 million tonnes, compared to 40 million tonnes last year, it said in a press release.

Ozone, a molecule of oxygen, forms a thin layer in the stratosphere, filtering out dangerous ultraviolet sunlight that damages vegetation and can cause skin cancer and cataracts.

The protectively layer has been badly damaged by man-made chlorine-based chemicals.

The hole -- in essence, a thinning of the layer -- goes through a cycle each year as the chemical reaction that drives depletion peaks during the deep chill of the southern hemisphere winter, from late August to October.

In 2006, the ozone hole at its biggest measured 28 million square kilometers (10.81 million square miles); in 2007, it was 24.7 million sq. kms. (9.53 million sq. miles), or roughly the size of North America.

Ronald van der A, a senior project scientist at Royal Dutch Meteorological Institute (KNMI), said this year's improvement could not be seen as a confirmation that the ozone layer was in recovery.

"This year's ozone hole was less centred on the South Pole as in other years, which allowed it to mix with warmer air, reducing the growth of the hole, because ozone is depleted at temperatures less than -78 degrees Celsius (- 108 degrees Fahrenheit)," he said.

Over the last decade, the ozone layer has thinned by about 0.3 percent per year on a global scale.

Last September 22, nearly 200 countries agreed to accelerate the elimination of hydrochlorofluorocarbons (HCFCs), a category of ozone-destroying chemicals.

Under the deal reached at a UN-sponsored conference in Montreal, developed countries will phase out the production of HCFCs by 2020 while developing states have until 2030 -- 10 years earlier than previously promised.

The agreement changes the timetable that had been set in 1987 under the Montreal Protocol, which aims to eliminate the use of HCFCs and similar chemicals once commonly found in refrigerators, fire retardants and aerosol sprays.

Graphic on the ozone layer. The European Space Agency (ESA) has said the ozone hole... 

Sensor-Rigged Helmet Gives Football Players a Heads Up on Concussions

Sensor-Rigged Helmet Gives Football Players a Heads Up on Concussions

An Illinois high school ponies up $60,000 for helmets designed to protect players against brain and spinal injuries

	Image: Courtesy of the University of Illinois
	SENSITIVE HELMET:  University of Illinois assistant professor Steven Broglio is working with Unity High School in Tolono, Ill., to study the effectiveness of Head Impact Telemetry System (HITS) technology for the school's football team.

As a high school running back stretches forward to get that extra yard, he is met with a ferocious blow to the head by the opposing team's linebacker. After a quick shake of the head to clear the cobwebs, the player returns to his team's huddle unaware that he's just sustained a concussion that could eventually affect his memory, judgment, reflexes, speech, balance and coordination.

Football parents take heart, some high school teams are now testing a new helmet sensor that promises to alert coaches when players have been hit hard enough to cause a concussion, potentially averting further brain injury.

Unity High School in Tolono, Ill., has equipped its 32 varsity football team members with special helmets that employ Head Impact Telemetry System (HITS) technology. The helmets—made by sports equipment maker Riddell Sports Group—use sensor technology developed by New Hampshire–based Simbex, LLC. The system consists of six battery-powered sensors in the helmet's padding that record the location, magnitude, duration and direction of up to 100 impacts and wirelessly send this information to a PC (within 150 yards) running data collection software. The sensors work by measuring both linear and rotational acceleration of the helmet after a player has been struck, although they add only negligible weight to the helmet itself.  

"We can pull up the profile of any player for that game or practice and see every impact he took in any given practice or game," says Steven Broglio, an assistant professor in the University of Illinois at Urbana-Champaign's Department of Kinesiology and Community Health. Broglio is studying the use of HITS as part of his research on concussions, typically caused when a violent blow to the head causes the brain to slide forcefully against the inner wall of the skull.

Image: Courtesy of the University of Illinois
ANATOMY OF A CONCUSSION:  The helmets use sensors to record the location, magnitude, duration and direction of any impact to a player's head.

The greatest sticking point to the technology is its price tag: Unity High spent about $30,000 for the fully equipped, waterproof computer and about $1,000 per helmet. Only a handful of football players at high schools in Pennsylvania and Oklahoma are also testing the helmets, Broglio says.

HITS was developed in 2002 by researchers at Virginia Polytechnic Institute and Dartmouth College. It was used to monitor head blows sustained by members of the Virginia Tech Hokies NCAA Division I football team during 10 games and 35 practices in the 2003 season, becoming the first technology to record real-time head-impact acceleration levels in actual practice and game situations for each player on a team. Results indicated that players experience as many as 50 significant hits each game, enduring head-acceleration levels similar to those seen in automobile crashes. HITS has also been used by amateur boxers as well as by members of the Dartmouth ice hockey team and University of North Carolina at Chapel Hill athletes.

At the beginning of the season, each Unity High player was given a 25-minute, computer-based test to establish his baseline brain behavior. During this testing, each player performed tasks such as counting backward and placing objects in order. If a player is injured, or an injury is suspected, the high school will administer the test again and compare the results captured by HITS; any major deviation in results could signal to the team that a player has sustained a concussion.

HITS has already indicated that one Unity football player this season was using the top of his helmet to tackle, a dangerous practice that could lead to spinal cord injuries. The heads up, so to speak, gave his coaches the opportunity to correct this bad habit before it caused damage, Broglio says. Unity football head coach Scott Hamilton says he is pleased with system, adding, "Anything to protect our kids is a wonderful concept."

Of the 1.2 million high school football players in the U.S., as many as 5.6 percent experience a concussion during the season, according to research by Kevin Guskiewicz, chairman of U.N.C.'s Department of Exercise and Sport Science. He also found that players who sustained one concussion in a season were three times more likely than uninjured players to sustain another in the same season.

Guskiewicz has also studied the impact of concussions on former National Football League players. Earlier this year, he reported: of the 2,552 retired NFL players he studied, the 595 with a history of three or more concussions were 20 percent more likely to develop clinical depression than those who had not suffered a concussion. The study also linked traumatic brain injury with the onset of neurodegenerative disorders, including mild cognitive impairment as well as Alzheimer's and Parkinson's diseases.  

The NFL, which criticized the size of Guskiewicz's research sample, has indicated that 98 g's is the typical minimum force at which an impact will cause a concussion, but "we've found that concussions also happen at higher and lower impacts," Broglio says.

Broglio is in discussions with Hamilton to continue his research at Unity next season and also hopes to sign up other high schools to test the helmets. Only then, he says, will he be able to determine whether HITS or some similar technology should be standard issue for athletes in contact sports.

Putting the Squeeze on Nanothreads to Spin Living Tissue

Putting the Squeeze on Nanothreads to Spin Living Tissue

Cell-size nanothreads spun from the tip of a needle that uses pressure rather than an electric charge promise novel regeneration treatments

	UNDER PRESSURE:  By applying pressure around the outside of a special needle, scientists can spin a nanosize thread of living cells.

Scientists using an electrically charged needle have electrospun nanosize threads of cells encased in plastic polymers to create living microfibers that promote tissue regrowth. Unfortunately, the electrical charge can hurt both the spun cells and the scientists doing the spinning. But now mechanical engineers Suwan Jayasinghe and Sumathy Arumuganathar of University College London have invented a way to spin nanothreads using only pressure and, with the help of medical colleagues, shown that they can create such nanothreads of living heart tissue, potentially revealing the way to weave an entirely new, healthy heart or even fresh, new skin.

"[We can] remove the electric field and use pressure to draw the fibers," Jayasinghe says. "You can make scaffolds with living cells with this technique as well, which shows that this technique can be used right across the board."

The researchers successfully used this method to spin tissue from smooth muscle cells from rabbit aortas with a special device comprising three concentric needles: an inner needle pushing out the cells, a second needle ejecting an encasing polymer, and a third, surrounding needle that applies pressure. By flowing the cells at a slow rate, the polymer at a slightly faster rate, and applying pressure (ranging from slightly less to nearly double that of the atmosphere), Jayasinghe and his colleagues teased out a microthin, continuous thread. "Some of the simplest things in life are some of the things that are unexplored," Jayasinghe says. "Increase the pressure and you get thinner fibers."

 

Cells that were subjected to such pressures showed no immediate ill effects nor any three weeks later compared with untreated controls, according to a paper outlining the findings online in Biomedical Materials. The technique may allow researchers to create living scaffolds of cells to deliver drugs as well as grow or regenerate the heart and other organs.

Image: COURTESY OF SUWAN JAYASINGHE
LIVING SCAFFOLD:  Scaffolds of living nanofibers, pictured here, could allow the regeneration or regrowth of tissue, ranging from skin to entire organs such as the heart.

But unlike electrospinning, the new method does not currently allow researchers to easily align living cells, Jayasinghe notes. The natural concentrations of charged molecules in such cells line them up when exposed to an electrical charge, as long as the cells are evenly spaced. In contrast, the pressure technique tends to deliver cells in clusters but researchers say the problem may be solved by smoothing out the spacing of the cell mixture.

Regardless, the novel technique will allow engineers to play with new types of materials, such as metal nanoparticles that would have disrupted an electrical charge. "You can directly thread very highly conducting composite materials to polymers that were previously unexplored," Jayasinghe says.

The team is now testing the gene production of the resultant cellular nanothreads to determine their safety. "You wouldn't want to put cancerous cells back into anybody's body," Jayasinghe notes. He adds that researchers are also exploring the potential of spinning such nanothreads from stem cells. "Stem cells will differentiate into anything," he says. "They can go on your heart or on your skin, they can go anywhere."

Solar Storm Rips Tail Off Comet

Solar Storm Rips Tail Off Comet

A storm from the sun ripped a tail off a comet, and a NASA satellite captured the whole event.

The spectacular cosmic crash occurred on April 20 when the sun cast out a coronal mass ejection (CME), or large cloud of magnetized gas. The tempest was thrust directly in the path of Comet Encke, which was traveling around the sun, within the orbit of Mercury. As the gas swept over the comet, its tail brightened and then was separated completely from its parent icy rock and carried away.

NASA's pair of Solar Terrestrial Relations Observatory (STEREO) satellites captured the whole incident in newly released images and video.

"We were awestruck when we saw these images," said Angelos Vourlidas of the Naval Research Laboratory. "This is the first time we've witnessed a collision between a coronal mass ejection and a comet, and the surprise of seeing the disconnection of the tail was the icing on the cake."

Comets are icy leftovers from the solar system's formation billions of years ago. They occasionally detour from their home in the cold, distant regions of the solar system, after a gravitational tug from a planet or another comet sends them into the inner solar system.

The sun's heat vaporizes gas and dust from the ice core of the comet, forming its tail.

CMEs are violent eruptions on the sun, with masses upwards of a few billion tons traveling anywhere from 62 to 1,864 miles per second (100 to 3,000 kilometers per second). They can cause geomagnetic storms in the Earth's atmosphere, which can disrupt satellite and radio communications and sometimes disable satellites.

While scientists were aware that a comet's tail would occasionally completely disconnect and suspected CMEs were the culprit, this is the first observation of the violent event. 

This series of four still images were taken from an animation of Comet Encke flying through the solar storm as witnessed by the STEREO satellite. Note Encke's tail being torn off by the coronal mass ejection in the third still above. Credit: NASA