Researchers from the University of Notre Dame have engineered nanoparticles that show great promise for the treatment of multiple myeloma (MM), an incurable cancer of the plasma cells in bone marrow.
One of the difficulties doctors face in treating MM comes from the fact that cancer cells of this type start to develop resistance to the leading chemotherapeutic treatment, doxorubicin, when they adhere to tissue in bone marrow.
"The nanoparticles we have designed accomplish many things at once," says Başar Bilgiçer, assistant professor of chemical and biomolecular engineering and chemistry and biochemistry, and an investigator in Notre Dame's Advanced Diagnostics and Therapeutics (AD&T) initiative.
"First, they reduce the development of resistance to doxorubicin. Second, they actually get the cancer cells to actively consume the drug-loaded nanoparticles. Third, they reduce the toxic effect the drug has on healthy organs."
The nanoparticles are coated with a special peptide that targets a specific receptor on the outside of multiple myeloma cells. These receptors cause the cells to adhere to bone marrow tissue and turn on the drug resistance mechanisms. But through the use of the newly developed peptide, the nanoparticles are able to bind to the receptors instead and prevent the cancer cells from adhering to the bone marrow in the first place.
The particles also carry the chemotherapeutic drug with them. When a particle attaches itself to an MM cell, the cell rapidly takes up the nanoparticle, and only then is the drug released, causing the DNA of cancer cell to break apart and the cell to die.
"Our research on mice shows that the nanoparticle formulation reduces the toxic effect doxorubicin has on other tissues, such as the kidneys and liver," adds Tanyel Kiziltepe, a research assistant professor with the Department of Chemical and Biomolecular Engineering and AD&T.
"We believe further research will show that the heart is less affected as well. This could greatly reduce the harmful side-effects of this chemotherapy."
The group had to tackle three important problems associated with all nanoparticle-based therapies, explains Jonathan Ashley, one of the leading researchers of the project.
"There was some complex bioengineering involved in developing the particles. We were able to precisely control the number of drug and targeting elements on each nanoparticle, achieve homogeneous nanoparticle size distribution and eliminate the batch-to-batch variability in particle production."
Before advancing to human clinical trials, the team plans further research and testing to improve the design of the nanoparticles and to find the optimum amount and combination of chemotherapy drugs for this new treatment.
Read more at Science Daily
Jun 16, 2012
'Echoes' of the Big Bang Misinterpreted?
This is according to veteran radio astronomer Gerrit Verschuur, of the University of Memphis, who has an outrageously unorthodox theory that if true, would turn modern cosmology upside down.
He proposes that at least some of the fine structure seen in the all-sky plot of the universe's cosmic microwave background is really the imprint of our local interstellar neighborhood. It has nothing to do with how the universe looked 380,000 years after the Big Bang, but how nearby clouds of cold hydrogen looked a few hundred years ago.
The idea is so unbelievable that it's little wonder that cosmologists have largely ignored his work that has been published over the last few years.
"Science is supposed to be about the excitement of making new discoveries. But this discovery terrifies me," he told reporters at the recent meeting of the American Astronomical Society in Anchorage, Alaska.
Verschuur's radio maps of hydrogen surrounding our local stellar neighborhood out to a few hundred light-years appear to have an uncanny match-up to the mottled structure of the cosmic microwave background that is 13.7 billion light-years away.
NASA's Wilkinson Microwave Anisotropy Probe (WMAP) mapped the CMB in exquisite detail in 2003. The data show the slight temperature fluctuations in the early universe that are believed to be the seeds of galaxy formation. It is a landmark observation that is considered the "blueprint" for the subsequent evolution of the universe.
Verschuur is quick to applaud the WMAP team for a "brilliant experiment" to attempt to resolve the structure of the primeval universe as encoded in ancient microwave radiation. But he suggests that the team failed to subtract all the foreground radio phenomena that may have contaminated the data.
Peaks in the foreground radio emission appear to overlay the peaks in the warmest region of the background, or appeared slightly offset.
In 2007 and 2010, Verschuur published a list of over 100 apparent matches between the CMB pattern and his interstellar hydrogen pattern.
Verschuur would have dismissed this as an odd coincidence until he realized that small interstellar clouds of hydrogen collide and jostle electrons to generate high-frequency radio emissions.
Like other foreground sources this would overlay the CMB. Because the WMAP team didn't consider or know about the contribution of such a phenomenon they didn't try and subtract it as they did numerous other electromagnetic "contaminants" in their data reduction, says Verschuur.
If Verschuur's theory is correct, the consequences would send seismic waves through the cosmology community. It implies that at least some of the small-scale structure in the CMB map doesn't exist at all.
But hold on. Detailed analysis of the angular diameter of CMB blobs yield a power spectrum that exactly fits theoretical predictions. The first peak in the spectrum shows a geometrically flat universe. The next peak determines the density of normal matter. The third peak provides information about the density of dark matter. And it all fits together beautifully.
Verschuur shrugs off the interpretation, saying that astronomers can analyzed the data and then stop when, "they find what they are looking for.
Astrophysicists Kate Land and Anze Slosar conducted an analysis of Verschuur's study that was published in the Dec. 10, 2007, edition of The Astrophysical Journal. In an email to Wired, they concluded that Verschuur's correlation of the radio emissions from nearby hydrogen and the WMAP data was nothing more than a coincidence.
"Notoriously, by eye, one can often think they see correlations between patterns," Land told Wired. "But one doesn't really see the anti-correlations. So two maps (of the sky) that just fluctuate randomly can appear correlated."
Read more at Discovery News
Jun 15, 2012
Persistence Is Learned from Fathers, Study Suggests
BYU professors Laura Padilla-Walker and Randal Day arrived at these findings after following 325 families over several years. And over time, the persistence gained through fathers lead to higher engagement in school and lower rates of delinquency.
"In our research we ask 'Can your child stick with a task? Can they finish a project? Can they make a goal and complete it?'" Day said. "Learning to stick with it sets a foundation for kids to flourish and to cope with the stress and pressures of life."
The scholars from BYU's School of Family Life report their findings June 15 in the Journal of Early Adolescence.
"There are relatively few studies that highlight the unique role of fathers," Padilla-Walker said. "This research also helps to establish that traits such as persistence -- which can be taught -- are key to a child's life success."
The key is for dads to practice what's called "authoritative" parenting -- not to be confused with authoritarian. Here are the three basic ingredients:
- Children feel warmth and love from their father
- Accountability and the reasons behind rules are emphasized
- Children are granted an appropriate level of autonomy
About 52 percent of the dads in the study exhibited above-average levels of authoritative parenting. Over time, their kids were significantly more likely to develop persistence, which lead to better outcomes in school and lower levels of delinquency.
This particular study examined 11-14 year olds residing in two-parent homes. Yet the study authors suggest that single parents still may play a role in teaching the benefits of persistence, which is an avenue of future research.
"Fathers should continue to try and be involved in their children's lives and engage in high quality interactions, even if the quantity of those interactions might be lower than is desirable," Padilla-Walker said.
Read more at Science Daily
Grasshoppers Frightened by Spiders Affect Whole Ecosystem
How do grasshoppers who are being frightened by spiders affect our ecosystem? In no small measure, say researchers at the Hebrew University of Jerusalem and at Yale University in the US.
A grasshopper who is in fear of an attacker, such as a spider, will enter a situation of stress and will consume a greater quantity of carbohydrate-rich plants -- similar to humans under stress who might eat more sweets.
This type of reaction will, in turn, cause chemical changes in the grasshopper and in its excretions, affecting the ecosystem it inhabits. How does this happen?
When the scared grasshopper dies, its carcass, now containing less nitrogen as a result of its diet change, will have an effect on the microbes in the ground, which are responsible for breaking down animals and plants.
With less nitrogen available, the microbes will be decomposing the hard-to-break-down plant materials in the soil at a slower rate. Thus, the fear of predation may slow down degradation of complex organic materials to the simpler compounds required for plant growth.
Research on this biological-ecological phenomenon was carried out by Dr. Dror Halwena of the Department of Ecology, Evolution and Behavior at the Alexander Silberman Institute of Life Sciences at the Hebrew University of Jerusalem, in cooperation with researchers at Yale University in the United States. An article on their research appears in the current edition of the journal Science.
In their research, the scientists exposed grasshoppers to spiders in order to arouse the stress reaction. They also used a control group of non-stressed grasshoppers. The scared grasshoppers had a higher carbon-to-nitrogen ratio in their bodies than non-scared grasshoppers.
In further laboratory and field tests, the researchers tested the influence of remains of grasshoppers from the two groups on soil. After the microbes consumed the grasshopper remains, the researchers added plants to the surface. In the experiments, it was shown that the decomposition rate of the plants in the areas in which the stress-free grasshopper remains were introduced decomposed at a rate between 62 and 200 percent faster than in the samples in which the stressed grasshopper s were put.
In a further experiment, the researchers used "artificial grasshoppers" -- a mixture of sugar, protein, and chitin (the organic compound found in the grasshopper external skeleton) -- in varying quantities. Here, too, they found that even a small amount of nitrogen (found in the protein) added to the soil increases significantly the functioning of the microbes responsible for breaking down the organic matter in plants.
"We are dealing here with an absolutely new kind of mechanism whereby every small chemical change in a creature can regulate the natural cycle, thus in effect affecting the ecology in total, such as the amount of carbon dioxide released into the atmosphere (through decomposition) and field crop productivity. This has tremendous consequences for our ecological understanding of the living world," said Dr. Halwena.
"We are gaining a greater understanding of the necessity of conserving all of the component parts of the ecosystem in general and of predators in particular. We are losing predators in nature at a much faster rate than other species," Dr. Halwena commented.
Read more at Science Daily
Hitchhiking Adventures of Pre-Columbian Yeast
A particular strain of yeast was identified in three far flung corners of the globe: eastern Australia, Costa Rica and the Galapagos Islands. The yeast, a variety of Saccharomycopsis fodiens, was not found anywhere else, though microbiologists isolated thousands of different yeast strains growing on sap beetles, the microbes' preferred habitat.
How the S. fodiens strain got to such distant locales without leaving traces in between is a mystery. One possibility is that they hitched a ride with human travelers.
"The collection sites for S. fodiens are compatible with the hypothesis that ancient Polynesians migrated southward from Taiwan and then eastward across the Pacific and eventually South America carrying sweet potato plants, whose flowers carry similar insects and yeasts," said Marc- André Lachance of Western Ontario University, who led the research, in a press release.
A problem with that hypothesis is that the sweet potato is native to the Western Hemisphere, along with all of its spud relatives. But that doesn't mean sweet potato plants and the beetles and yeast hitching a ride on them couldn't have gone from South America out into the Pacific.
The Maori of New Zealand were growing a variety of sweet potato long before Europeans spread the plant around the world, as were other Polynesian people to the east. Radiocarbon dating of sweet potato remains on the Cook Islands found them to be approximately 1,000 years old.
Although Thor Heyerdahl proved people could travel west from South America into the Pacific with the potato in tow, it seems more likely that the Polynesians, with their mastery of long distance navigation, would have been the culture that made it across the Pacific to South America. The seafaring spud-bearers could have then turned back around and brought potatoes to the Pacific.
The Polynesians might not have been alone on their voyages. Some suggest that chickens made the crossing with them, then stayed in South America.
Read more at Discovery News
17th Century Postal System Carved in Stone
Carved between 1601 and 1657 by sailors aboard Dutch East India Company ships on their way to the East Indies, the stones often featured letters placed at their base. The missives, carefully wrapped in layers of canvas, tar and lead envelopes, were left for other ships to pick up.
"The idea was that the crew of the next Dutch ship to anchor in that same place would pen down the message on the rock and collect the letters," Wendy van Duivenvoorde, a lecturer in maritime archaeology at Flinders University, Adelaide, Australia, told Discovery News.
"Basically it was like an early postal system," she said.
In the 1500s, the Portuguese were the only Europeans who knew the route to South East Asia so they supplied all the spices and exotic goods to the Netherlands.
As the Dutch made their way to Batavia (modern day Jakarta) for the first time in 1595, they realized they didn't have any systems in place to communicate via other Dutch ships to send messages back home and relay their last port of call.
From the first voyage on, they went to a small beach in the Antongil Bay on the northeast corner of Madagascar.
"They started using the beach as a communications area by inscribing messages on the rock faces and frequently leaving letters for other ships to pick up," she added.
About a dozen of these inscriptions were discovered in the early 1920s, but the recent expedition, led by van Duivenvoorde under the auspices of the Australian Research Council, was the first to conduct a detailed archaeological assessment of the rock carvings within their environment.
The team, which included Mark Polzer, a research associate in archaeology at Flinders University, and Jane Fyfe, a Ph.D. candidate and rock art specialist from the University of Western Australia, discovered more than 40 inscriptions left by at least 13 different ships.
The carved messages revealed official communications that recorded the names of ships, the times and dates of their arrivals and other such details.
They also showed unofficial messages left by higher-ranking seamen, who carved their names into the stone.
"That was much as someone today might write, 'Hendrick was here'," van Duivenvoorde said.
According to the researcher, the earliest inscriptions dated to 1601 and were carved by the crew of the fifth Dutch expedition to the Indies—one year before the official founding of the Dutch East India Company in 1602.
One carving reveals that the ship Middelburg reached the bay after a cyclone in 1625 without masts, and was anchored there for seven months while it was being repaired.
"It’s quite amazing to think that they managed to sail into the bay after suffering such damage," van Duivenvoorde said.
A few inscriptions reveal that letters were left beneath them.
"These stones are really part of an early Dutch postal system and they show how European ships relayed information about their whereabouts when far away from home," van Duivenvoorde said.
"Unfortunately, should the next ship to arrive belong to their British or Portuguese rivals, the messages and letters would be absconded for their intelligence and to confound the Dutch," she said.
Read more at Discovery News
Jun 14, 2012
Still Capable of Adapting: Genetic Diversity of 'Living Fossil' Coelacanths
This is described by PD Dr. Kathrin Lampert from the RUB's Department of Animal Ecology, Evolution and Biodiversity along with colleagues from Würzburg, Bremen, Kiel and Dar es Salaam (Tanzania) in the journal Current Biology. "Coelacanths are rare and extremely endangered. Understanding the genetic diversity of these animals could help make preservation schemes against their extinction more effective" says the biologist.
Different populations in Africa studied
Previous genetic studies focused mainly on the biological relationships of coelacanths to lungfish and and vertebrates. In order to assess whether the fish are still able to adapt to new environmental conditions, however, you have to know the genetic diversity within the species. For this purpose, the research team examined 71 specimens from various sites on the east coast of Africa. The researchers analysed genetic markers from the nucleus and from the mitochondria, the powerhouses of the cells.
Geographical differences in the genetic makeup
The data generally revealed low genetic diversity. As presumed, the evolution of these animals is only progressing slowly. Nevertheless, certain genetic patterns were only found in certain geographic regions. "We assume that the African coelacanth originally came from around the Comoros Islands, home to the largest known population" Lampert explains. Since then, however, two further, now independent populations have established themselves in South Africa and Tanzania. In addition, the animals around the Comoros belong to two genetically distinct groups. "We have thus been able to show that despite their slow evolutionary rate, coelacanths continue to develop and are potentially also able to adapt to new environmental conditions" says the RUB researcher. "The image of the coelacanth as a passive relic of bygone times should therefore be put into perspective."
Read more at Science Daily
First Painters May Have Been Neanderthal, Not Human
That’s not yet certain: The paintings may have been made by humans at an unexpectedly early date, which would itself raise intriguing questions, though none so tantalizing as Neanderthal painters.
“It would not be surprising if the Neanderthals were indeed Europe’s first cave artists,” said João Zilhão, an archaeologist at Spain’s University of Barcelona, at a press conference on June 13.
Researchers led by Zilhão and Alistair Pike of the United Kingdom’s University of Bristol measured the ages of 50 paintings in 11 Spanish caves. The art, considered evidence of sophisticated symbolic thinking, has traditionally been attributed to modern humans, who reached Europe about 40,000 years ago.
Traditional methods of dating cave paintings, however, are relatively clumsy. Even the previous best technique — carbon dating, or translating amounts of carbon molecule decay into measurements of passing time — couldn’t discern differences of a few thousand years.
Instead of carbon, Pike and João Zilhão’s team calibrated their molecular clocks by studying mineral deposits that form naturally on cave surfaces, including paintings. The thicker the deposits, the older the painting. And as the researchers describe in a June 14 Science paper, some of the paintings are very old indeed.
Some handprint outlines are at least 37,000 years old. Several red circles are at least 41,000 years old and may be several thousand years older. That’s 10,000 years older than paintings in France, which until now were considered the oldest cave art.
If H. sapiens made the Spanish paintings, they would have needed to arrive in Europe already possessing a symbolic art tradition, something for which there’s no other evidence.
Alternatively, humans may have arrived in Europe and promptly learned to paint, raising the question of why such an important cultural leap occurred so suddenly, in that particular place. Maybe something about the environment, such as competition with Neanderthals, made symbolic thinking important.
Or — and this is still just a hypothesis, one that needs to be tested by dating of many more paintings — the artists were not human. Maybe they were Neanderthals.
If so, the paintings would be a pièce de résistance addition to a decade of Neanderthal research that’s showed how our closest evolutionary relatives, long considered less intelligent than humans, were truly sophisticated thinkers capable of symbolism, social planning and empathy. Paintings would provide the last bit of evidence needed to throw out the image of Neanderthals as archetypally dumb, Zilhao said.
“What’s really exciting about this possibility,” said Pike, “is that anyone, because it’s open to the public, could walk into El Castillo cave and see a Neanderthal hand on the wall.”
Read more at Wired Science
Carnivorous Plant Catapults Ants
The type of carnivorous plant, the pitcher plant of the species Nepenthes gracilis, lines the underside of its lid with a special waxy coating, which makes sure ants and flies will lose their grip when a raindrop falls and shakes the lid they are clutching. (The ants and flies walk upside-down on the underside of this lid.) The plant gets its name from its pitcher, the large empty structure that holds the digestive enzymes that churn up its fly meals and is covered by the waxy lid.
"Basically it works a bit like a springboard in a pool, but the other way around," study researcher Ulrike Bauer, of the University of Cambridge in the United Kingdom, told LiveScience. "The reason why it works is it has a specialized waxy coating on the lower lip surface."
Flipping its lid
By replacing this waxy surface with a smooth one in the lab, the researchers were able to show that this covering is specially created by the plant to have just enough grip for the ants to hang on to normally, but when hit with a raindrop or other vibration-producing stimulus, the ants are no longer able to grip and fall straight into the pitcher.
The ants and flies are attracted to the bottom of the lid because the plants excrete a sugary nectar from the lid. It is also a good place to hide during a rainstorm, especially if the bug has delicate wings, Bauer said. Instead these bugs "end up in the pitcher fluid instead of finding a safe and dry place."
Using medium-size lab-created raindrops, the researchers were able to knock about 40 percent of the ants off the lid and into the pitcher. The researchers also took high-speed video of the movements.
"The raindrops hit the pitcher lid from above and that makes the lid move quickly downward and that's where we think the insects then get flicked off," Bauer said.
Wax on, wax off
The researchers also took a closer look at the waxy surface on the underside of the lid using scanning electron microscopy.
"If you look at a high magnification under a microscope, you can see it's a structure made up of wax pillars situated very close together," Bauer said. "What that does is it makes the surface slightly slippery, but not completely slippery. It's safe enough for the insect to walk upside-down under normal conditions, but not when the lid is hit by a raindrop — it starts to vibrate and that's enough for the insect to fall off."
Read more at Discovery News
Huge Asteroid to Fly by Earth Thursday
The near-Earth asteroid 2012 LZ1, which astronomers think is about 1,650 feet (500 meters) wide, will come within 14 lunar distances of Earth Thursday evening. While there's no danger of an impact on this pass, the huge space rock may come close enough to be caught on camera.
That's what the team running the Slooh Space Camera thinks, anyway. The online skywatching service will train a telescope on the Canary Islands on 2012 LZ1 and stream the footage live, beginning at 8:00 p.m. EDT Thursday (0000 GMT Friday).
You can watch the asteroid flyby on Slooh's website, found here: http://events.slooh.com/
2012 LZ1 just popped onto astronomers' radar this week. It was discovered on the night of June 10-11 by Rob McNaught and his colleagues, who were peering through the Uppsala Schmidt telescope at Siding Spring Observatory in Australia.
Researchers estimate that the space rock is between 1,000 and 2,300 feet wide (300-700 m). On Thursday evening, it will come within about 3.35 million miles (5.4 million kilometers) of our planet, or roughly 14 times the distance between Earth and the moon.
Because of its size and proximity to Earth, 2012 LZ1 qualifies as a potentially hazardous asteroid. Near-Earth asteroids generally have to be at least 500 feet (150 m) wide and come within 4.65 million miles (7.5 million km) of our planet to be classified as potentially hazardous.
Read more at Discovery News
Jun 13, 2012
Distant Human Ancestor Had Shark Head
In fact, this now-extinct fish was among the first to split from sharks, whose bones are made of cartilage, to evolve into a line of tough-boned species that includes everything from bony fish to human beings. A new analysis finds that this controversial class of animals was more shark-like than expected.
"The common ancestors of all jawed vertebrates today organized their heads in a way that resembled sharks," study researcher John Finarelli, a vertebrate biologist at University College, Dublin, said in a statement. "Given what we now know about the interrelatedness of early fishes, these results tell us that while sharks retained these features, bony fishes moved away from such conditions."
Finarelli and his colleagues examined a fish called Acanthodes bronni, part of the acanthodian group of fish, which included the earliest vertebrate animals with jaws. A. bronni lived about 290 million years ago, during the Paleozoic period. The shark family and the bony fish families split about 460 million years ago.
A. bronni left few traces besides its fossil scales and fin spines. But a few fossilized, fragmented skulls survived millions of years in the ground and now reside in museum collections. The researchers made silicone rubber casts of these fossils in order to reconstruct the anatomy of the fish's heads.
This closer-than-ever look revealed ridges and grooves never before examined. The researchers took 138 characteristics of the skulls and compared them with both the skulls of the chondrichthyes, the group made up of sharks and rays, and the osteichthyes, or bony fish such as today's sardines and mackerel. They found that on the whole, acanthodian heads fell in with the sharks.
"For the first time, we could look inside the head of Acanthodes, and describe it within this whole new context," study researcher Michael Coates, a University of Chicago biologist, said in a statement. "The more we looked at it, the more similarities we found with sharks."
The study also revised the relationships between early gnathostomes, or vertebrates with jaws (whose members range from fish and sharks to birds, reptiles and humans), and the most primitive members of that group, armored fish called placoderms. The researchers found distinctive anatomical differences between placoderms and other gnathostomes.
Read more at Discovery News
'Nonad' Spiders Lose Gonads to Fight Better
Associate Professor Daiqin Li from the National University of Singapore, and colleagues, report their findings today in Biology Letters.
"The eunuch males are better fighters because they are lighter and they have an increased endurance," says Li, an expert in animal behavior.
"They try to prevent the other males from mating with the female."
In a number of spider species, the females are much larger than the males and more aggressive.
Li and colleagues studied one tropical species called Nephilengys malabarensis in which the female cannibalizes the male during copulation.
Not only that, but what has really puzzled researchers until now is that during mating the males break off one or both of their sperm-containing palps.
The palps, which look a bit like boxing gloves, have a tube attached which is inserted into the female to enable sperm to be transferred.
When the palps break off they remain attached to the tube and sit on the outside of the female's body blocking her reproductive tract.
This had led to some scientists to speculate that spiders castrate themselves to create a "mating plug" that continuously transfers sperm to the female after the male is gone - and at the same time stops competing males from inserting their sperm.
But other males can easily remove the mating plug, says Li, which called for other explanations for the emasculating behavior.
Li says scientists had noticed that the 25 percent of males that survive the terrifying ordeal of mating are better fighters.
One hypothesis is that castrated males are better fighters because they are not weighed down by their manhood and thus have more energy to fight off competing males.
"Relatively the palps are heavy compared to the whole body mass," says Li. "If they remove one or two palps, they become significantly lighter compared to the intact male and are able to run faster and longer.
Li and team tested this "gloves off" hypothesis by creating spiders with one or both palps removed.
He says the design of the palps mean they break off easily and his team used forceps to emulate this natural process.
They then weighed the half-eunuch and full-eunuch spiders and compared their weight to intact males.
Finally, they tested the endurance of the three types of spiders by prodding them to run around and measuring the time it took the spiders to get exhausted.
Read more at Discovery News
Earth Worlds Common, Pre-Earth ETs Possible
Planets up to about four times the diameter of Earth form under a broader range of environmental conditions than gas giant planets, the analysis shows.
Scientists looked at 152 stars hosting planets or suspected planets that are Neptune-sized or smaller. They found that small planets, unlike gas giants, don’t need metal-rich parent stars to form.
“Our analysis based on the Kepler planet candidates indicates that terrestrial planets can form at a wide range of metallicities, including metallicities almost four times lower than that of the sun,” wrote lead author Lars Buchhave, with the Niels Bohr Institute at the University of Copenhagen.
The study, published this week in Nature, has several interesting implications. For one, since so-called metal-poor stars -- those made of just hydrogen and helium -- developed before metal-rich ones, planets around these stars (which formed from the same raw materials as their parent stars) didn’t have the right stuff for life, at least life as we know it.
“The elements from which planets and our bodies are made did not exist,” Yale University astronomer Debra Fischer noted in a related Nature paper.
But knowing that the formation of rocky planets can occur in lower-metal environments than those of gas giants lowers the bar for what it takes to create an Earth-like world, since they can form around a bigger range of stars, so it may have been easier for earths and earth-like life to form.
Read more at Discovery News
Large Eruptions Could Eat Away at Ozone Layer
Such a volcanic eruption could double or triple the current levels of the chemical elements bromine and chlorine in the stratosphere, the upper atmosphere layer where ozone gas protects us from ultraviolet radiation, the researchers calculated, based on the levels of these chemicals released from 14 volcanoes in Nicaragua over the past 70,000 years. The researchers presented their work at a scientific conference in Iceland.
Bromine and chlorine need an electron to become stable, and can easily rip it off passing molecules, like ozone. They are gases that "love to react — especially with ozone," study researcher Kirstin Krüger, a meteorologist with GEOMAR in Kiel, Germany, explained in a statement. "If they reach the upper levels of the atmosphere, they have a high potential of depleting the ozone layer."
To estimate the past release of these chemicals by volcanoes, the researchers measured levels of halogens (the group of highly reactive elements that bromine and chlorine belong to) in rock layers deposited before and after historic eruptions. The average eruption released two to three times the quantity of human-produced bromine and chlorine currently in the stratosphere, they found.
"As we have bromine and chlorine together, we believe that this can lead to substantial depletion," Krüger said. "And this is from one single eruption."
Previous studies have estimated that in large, explosive eruptions — the type that sends mushroom clouds of ash miles high — up to 25 percent of the ejected halogens can reach the stratosphere.
Because the effects are in the stratosphere, where the volcanic gases can be carried across the globe, eruptions of tropical volcanoes could lead to ozone depletion over a large area, even having an impact over Antarctica and the Arctic, where seasonal "holes" in the ozone layer already exist.
Read more at Discovery News
Jun 12, 2012
Mosquitoes Bred to Be Incapable of Transmitting Malaria
Anthony James and colleagues from UCI and the Pasteur Institute in Paris have produced a model of the Anopheles stephensi mosquito -- a major source of malaria in India and the Middle East -- that impairs the development of the malaria parasite. These mosquitoes, in turn, cannot transmit the disease through their bites.
"Our group has made significant advances with the creation of transgenic mosquitoes," said James, a UCI Distinguished Professor of microbiology & molecular genetics and molecular biology & biochemistry. "But this is the first model of a malaria vector with a genetic modification that can potentially exist in wild populations and be transferred through generations without affecting their fitness."
More than 40 percent of the world's population lives in areas where there is a risk of contracting malaria. According to the Centers for Disease Control & Prevention, 300 million to 500 million cases of malaria occur each year, and nearly 1 million people die of the disease annually -- largely infants, young children and pregnant women, most of them in Africa.
James said one advantage of his group's method is that it can be applied to the dozens of different mosquito types that harbor and transmit the Plasmodium falciparum parasite, including those in Africa. Study results appear this week in the early online version of the Proceedings of the National Academy of Sciences.
The researchers conceived their approach through mouse studies. Mice infected with the human form of malaria create antibodies that kill the parasite. James' team exploited the molecular components of this mouse immune-system response and engineered genes that could produce the same response in mosquitoes. In their model, antibodies are released in genetically modified mosquitoes that render the parasite harmless to others.
"We see a complete deletion of the infectious version of the malaria parasite," said James, a member of the National Academy of Sciences. "This blocking process within the insect that carries malaria can help significantly reduce human sickness and death."
He and his colleagues have pioneered the creation of genetically altered mosquitoes that limit the transmission of dengue fever, malaria and other vector-borne illnesses.
Read more at Science Daily
How Aging Is Recorded in Our Genes
DNA is made up of four basic building blocks — adenine, thymine, guanine, and cytosine — and the sequence of these nucleotides within a gene determines what protein it makes. Genes can be switched on and off as needed, and the regulation of genes often involves what are called epigenetic mechanisms in which chemical alterations are made to the DNA. One of the most common of these epigenetic changes involves a methyl group — one carbon atom and three hydrogen atoms — binding to a nucleotide, usually cytosine. In general, this binding, called methylation, turns off the gene in question.
Recent research suggests that changes in DNA methylation patterns as a person gets older may contribute to human diseases for which risk increases with age, including cancer. To get a better idea of how methylation patterns change with age, a team led by Manel Esteller, an epigenetics researcher at the Bellvitge Biomedical Research Institute in Barcelona, Spain, looked at two extreme cases: A newborn male baby and a man aged 103 years.
The team extracted DNA from white blood cells taken from the blood of the elderly man and from the umbilical cord blood of the baby and determined its methylation pattern using a fairly new technique called whole-genome bisulfite sequencing (WGBS). With WGBS, DNA is exposed to the chemical sodium bisulfite, which has no effect on cytosines with methyl groups bound to them but turns nonmethylated cytosines into another nucleotide called uracil. The result is an epigenetic map (see illustration) that shows exactly which DNA sites are methylated and which are not.
As the team reports online today in the Proceedings of the National Academy of Sciences, it found a significantly higher amount of cytosine methylation in the newborn than in the centenarian: 80.5 percent of all cytosine nucleotides, compared with 73 percent. To look at an intermediate case, the team also performed WGBS on the DNA of a 26-year-old male subject; the methylation level was also intermediate, about 78 percent.
Esteller and his colleagues then took a closer look at the differences between the DNA of the newborn and of the centenarian, but restricted the comparison to regions of the genome where the DNA nucleotide sequences were identical so that only the epigenetic differences would stand out. The team identified nearly 18,000 so-called differentially methylated regions (DMRs) of the genome, covering many types of genes. More than a third of the DMRs occurred in genes that have already been linked with cancer risk. Moreover, in the centenarian, 87 percent of the DMRs involved the loss of the methyl group, while only 13 percent involved the gain of one.
Finally, to expand the study, the team looked at the methylation patterns of 19 newborns and 19 people aged between 89 and 100 years old. This analysis confirmed that older people have a lower amount of cytosine methylation than newborns.
The authors conclude that the degree of methylation decreases in a cumulative fashion over time. Moreover, Esteller says, in the centenarian the loss of methyl groups, which turns genes back on, often occurred in genes that increase the risk of infection and diabetes when they are turned on during adulthood. In contrast, the small number of genes in the centenarian that had greater methylation levels were often those that needed to be kept turned on to protect against cancer.
Read more at Wired Science
Mammoths Wiped Out By Multiple Killers
Woolly mammoths (Mammuthus primigenius) wandered the planet for about 250,000 years, ranging from Europe to Asia to North America covered in hair up to 20 inches (50 centimeters) long and possessing curved tusks up to 16 feet (4.9 meters) long. Nearly all of these giants vanished from Siberia by about 10,000 years ago, although dwarf mammoths survived on Wrangel Island in the Arctic Ocean until 3,700 years ago.
Scientists have often speculated over what might have driven the mammoths to extinction. For instance, for years researchers suspected that ancient human tribes hunted the mammoths and other ice age giants to oblivion. Others have suggested that a meteor strike might have drastically altered the climate in North America about 12,900 years ago, wiping out most of the large mammals there, the so-called "Younger Dryas impact hypothesis."
Now an analysis of thousands of fossils, artifacts and environmental sites spanning millennia suggest that no one killer is to blame for the demise of the woolly mammoths.
"These findings pretty much dispel the idea of any one factor, any one event, as dooming the mammoths," researcher Glen MacDonald, a geographer at the University of California, Los Angeles, told LiveScience.
Mammoth database
Scientists investigated the extinction of woolly mammoths living in Beringia, the last refuge of mammoths that nowadays lies mostly submerged under the icy waters of the Bering Strait. To get an idea of woolly mammoth abundance, past climate and other environmental factors, they analyzed samples from more than 1,300 woolly mammoths, nearly 450 pieces of wood, nearly 600 archaeological sites and more than 650 peatlands, compiling their ages and locations to see how these giants and their environments changed over time. They also probed mammoth genetic data found in fossils of the titans.
"There will be people talking about the incompleteness of the fossil record, and there'll always be uncertainties here, no question, but the size of our database is thousands of data points, so I think we can see the general patterns," MacDonald said.
Their results revealed woolly mammoths flourished in the open steppe of Beringia between 30,000 to 45,000 years ago, with its relatively abundant grass and willow trees. The area wasn't as warm then as today, but not as cold as the height of the ice age. "That seemed to be very favorable for mammoths, in terms of abundance," MacDonald said. Humans coexisted with mammoths back then, clearly not driving them to extinction at that time.
Later, during the iciest part of the ice age 20,000 to 25,000 years ago, the "Last Glacial Maximum," northern woolly mammoth populations declined, likely because the area became too barren to be hospitable. However, during that time, the giants became abundant in the warmer interior parts of Siberia.
"There was an old idea that cold glacial conditions like the Last Glacial Maximum were optimal for mammoths," MacDonald said. "That idea now doesn't really hold water."
Northern refuge
Northern mammoth populations grew after the Last Glacial Maximum, but then dipped again during the Younger Dryas period about 12,900 years ago. Although there is controversy as to what happened at that time, "there was certainly a very rapid and profound cooling of many regions then, followed by rapid warming," MacDonald said. "Did this cause the extinction of the mammoth? Absolutely not. They were still present in far northern sites at the end of the Younger Dryas. Right now it's not quite definitive how great an impact the Younger Dryas had."
The last mammoths seen on the continents were concentrated in the north. They apparently disappeared about 10,000 years ago as the climate warmed and peatlands, wet tundra and coniferous forests developed, environments to which mammoths were poorly suited. The long-lasting proximity between mammoths and humans suggested that our species was perhaps a factor in the beasts' decline, possibly killing off the final island populations of woolly mammoths that went extinct 3,700 years ago.
Overall, these findings suggest the mammoths experienced a long decline due to many factors.
"There was no one event that ended the mammoths," MacDonald said. "It was really the coalescence of climate changeand the habitat change that triggered [it], and also human predators on the landscape at the end."
These findings regarding mammoths could shed light on what species today might face in the future.
Read more at Discovery News
Galaxy Close Encounter Created Giant Gas Bridge
Observations from the National Science Foundation's Green Bank Telescope, a massive radio instrument in Green Bank, W.Va., indicate that hydrogen gas may be streaming between the colossal Andromeda Galaxy, or M31, and its neighboring Triangulum Galaxy, or M33.
"The properties of this gas indicate that these two galaxies may have passed close together in the distant past," Jay Lockman, of the National Radio Astronomy Observatory (NRAO), said in a statement. "Studying what may be a gaseous link between the two can give us a new key to understanding the evolution of both galaxies."
These results were hinted at in a 2004 discovery, made by astronomers using the Westerbork Synthesis Radio Telescope in the Netherlands, but these early observations of a gaseous link between M31 and M33 were largely contested on technical grounds, the researchers said.
The new results, however, seem to indicate that astronomers' hunch eight years ago may have been correct. The highly sensitive Green Bank Telescope has not only confirmed the existence of the gaseous bridge, but has also found six dense clumps of gas within it.
Lockman and his colleagues examined these clumps and found that they share roughly the same relative velocity with respect to Earth as they do to the Andromeda and Triangulum galaxies. This indicates that they could be part of a bridge between the two neighboring structures, the researchers said.
The Andromeda and Triangulum galaxies are located approximately 2.6 and 3 million light-years from Earth, respectively. Both are members of the so-called Local Group of galaxies, which is made up of our own Milky Way and roughly 30 other galaxies.
When two galaxies pass close to one another, the encounter can cause gas from the galaxies being strewn across intergalactic space, creating a lengthy "tidal tail" between them.
Read more at Discovery News
Jun 11, 2012
Lessons from Epigenome Evolution
The sequencing of the human genome has provided a wealth of genetic information, yet the goal of understanding the function of every gene remains outstanding. New research from the University of Illinois published in Cell suggests determining the purpose of genes through a new method they call "comparative epigenomics."
"Comparative epigenomics is to use interspecies comparison of DNA and histone modifications -- as an approach for annotation of the regulatory genome," says Sheng Zhong, of the Institute for Genomic Biology and Department of Bioengineering at the University of Illinois.
While the genome of an organism contains all its genes, it is the epigenome that decides which are expressed, or "turned on." Though genomic science has long focused on comparative genomics -- comparing the genomes of similar species and finding the commonalities to determine how common traits are regulated -- comparative epigenetics provides a more in-depth look at regulatory functions.
The researchers, led by Zhong, in collaboration with Ting Wang at Washington University, Harris Lewin, and Franklin West at University of Georgia, focused their work on three species: humans, mice, and pigs. By analyzing 9 epigenomic marks in pluripotent stem cells, they were able to create an epigenomic map for each which they could then compare.
The team concluded that, with proper analysis procedures, traces of interspecies epigenomic conservation could be identified. They then demonstrated that the conserved epigenetic markers can be effectively used to annotate the genome, clarifying the genome's regulatory function.
Read more at Science Daily
"Comparative epigenomics is to use interspecies comparison of DNA and histone modifications -- as an approach for annotation of the regulatory genome," says Sheng Zhong, of the Institute for Genomic Biology and Department of Bioengineering at the University of Illinois.
While the genome of an organism contains all its genes, it is the epigenome that decides which are expressed, or "turned on." Though genomic science has long focused on comparative genomics -- comparing the genomes of similar species and finding the commonalities to determine how common traits are regulated -- comparative epigenetics provides a more in-depth look at regulatory functions.
The researchers, led by Zhong, in collaboration with Ting Wang at Washington University, Harris Lewin, and Franklin West at University of Georgia, focused their work on three species: humans, mice, and pigs. By analyzing 9 epigenomic marks in pluripotent stem cells, they were able to create an epigenomic map for each which they could then compare.
The team concluded that, with proper analysis procedures, traces of interspecies epigenomic conservation could be identified. They then demonstrated that the conserved epigenetic markers can be effectively used to annotate the genome, clarifying the genome's regulatory function.
Read more at Science Daily
China Unearths Over 100 New Terracotta Warriors
The life-size figures were excavated near the Qin Emperor's mausoleum in China's northern Xi'an city over the course of three years, and archaeologists also uncovered 12 pottery horses, parts of chariots, weapons and tools.
"The... excavation on the 200-square-metre (2,152-square-feet) site has found a total of 110 terracotta figurines," Shen Maosheng from the Qin Shihuang Terracotta Warriors and Horses Museum -- which oversees the tomb -- told AFP.
"The most significant discovery this time around is that the relics that were found were well-preserved and colourfully painted," Shen, deputy head of the museum's archaeology department, said.
He added that archaeologists had pinpointed the location of another 11 warriors but had yet to unearth them.
The discovery is the latest in China's cultural sector, after experts found that the Great Wall of China -- which like the Terracotta Army is a UNESCO World Heritage site -- was much longer than previously thought.
Shen said experts had expected the colours on some of the warriors and wares uncovered at the site to have faded over the centuries, and were surprised to see how well preserved they still were.
The finds also included a shield that was reportedly used by soldiers in the Qin Dynasty (221-206 BC), with red, green and white geometric patterns.
Qin Shihuang -- the Qin emperor who had the army built -- presided over the unification of China in 221 BC and is seen as the first emperor of the nation.
The ancient terracotta army was discovered in 1974 by a peasant digging a well. It represents one of the greatest archaeological finds of modern times, and was listed as a World Heritage Site in 1987.
The news comes after a five-year archaeological survey found the Great Wall of China was more than double the previously estimated length.
Read more at Discovery News
Tortoise Couple 'Divorces' After 115 Years
The fallout between the two tortoises, Bibi and Poldi, ends what was the world's oldest known animal "marriage."
As the zoo's director Helga Happ told the Austrian Times, "We get the feeling they can't stand the sight of each other anymore."
Signs of the breakup were not hard to detect. Bibi, seemingly tired of Poldi's attentions, hauled off and bit his shell one day. She later attacked him again, forcing the puzzled staff to move him to a separate enclosure.
The good news is that they did not decide to kill each other. Tortoises don't have teeth, but they do possess a horn-rimmed mouth and extremely powerful jaws. They could have easily done each other in. The zoo staff did not want to wait around for that to possibly happen.
Happ said, "They are both 115 years old -- they have been together since they were young and grew up together, eventually becoming a pair. But for no reason that anyone can discover they seem to have fallen out, they just can't stand each other."
She and other zoo staff are trying everything to save the marriage. They have given the pair "counseling," "romantic good food," and have tried to get the tortoises interested in "joint games," but all to no avail so far.
Bibi appears to be enjoying her new life as a single tortoise gal.
She and Poldi first met at the Basel Zoo in Switzerland. They then were moved together to the Austrian zoo in Klagenfurt, where were together for 36 years. Their routine hasn't changed much over the years.
Read more at Discovery News
Largest 'Dark Sky' Reserve Named
"The new reserve is coming in at a 'Gold' level status," said the International Dark-Sky Association's executive director Bob Parks in a statement. "That means the skies there are almost totally free from light pollution. To put it simply, it is one of the best stargazing sites on Earth."
To qualify to be a reserve, areas need to be endowed with dark skies and virtually no light pollution.
The new reserve includes Aoraki/Mt. Cook National Park and the Mackenzie Basin, and has been dubbed the "Aoraki Mackenzie International Dark Sky Reserve." It is the fourth such dark sky reserve in the world and covers more than 1,600 square miles (4,144 square kilometers).
This week's announcement coincides with the Third International Starlight Conference, a United Nations-led effort that emphasizes a star-filled night sky is part of the common heritage of mankind and that protections are necessary to ensure that present and future generations will be able to see the stars.
Last month, the IDSA announced the formation of the first such spot in Africa, the NamibRand Nature Reserve, a private nature reserve in southern Namibia.
Organizers of the new reserve in New Zealand recognize that the night sky played a critical role in the area's history as its first residents, the Maori, used it not only to navigate to the island but also made astronomy and star lore a part of their culture and daily lives. Mackenzie Basin has the clearest, darkest and most spectacular night sky in New Zealand, according to the IDSA statement.
Read more at Discovery News
Jun 10, 2012
New Anti-Cancer Vaccine Developed and Tested
Researchers at Moffitt Cancer Center have developed and tested in mice a synthetic vaccine and found it effective in killing human papillomavirus-derived cancer, a virus linked to cervical cancers among others.
The research was published in a recent issue of Cancer Immunology, Immunotherapy.
"Vaccines for cancer can be good alternatives to conventional therapies that result in serious side-effects and are rarely effective against advanced disease," said Esteban Celis, M.D., Ph.D., senior member and professor in Moffitt's Immunology Program. "The human papillomavirus, or HPV, is known to cause 99 percent of cervical cancers and annually causes more than 250,000 deaths worldwide." In addition, HPV is the causative agent of a large proportion of head and neck and genital cancers.
Although two approved prophylactic vaccines against strains of HPV that cause cervical cancer are now in wide use as a measure to prevent HPV infections, these vaccines cannot be used to treat HPV-induced cancers. Thus, there is a need to develop therapeutic vaccines for HPV-related tumors.
In an effort to find an effective HPV-cancer vaccine that would eliminate existing HPV-induced cancer, Celis and Kelly Barrios-Marrugo, Ph.D., of the University of South Florida College of Medicine's Molecular Medicine program, designed a peptide vaccination strategy called TriVax-HPV.
The TriVax vaccine strategy was designed to generate large numbers of cytotoxic T-cells that would seek out the proteins preferentially expressed in the tumors. The HPV16-E6 and E7 proteins function as oncogenic proteins inducing cancer. Thus, according to Celis and Barrios-Marrugo, a vaccine targeting these viral proteins is an "ideal candidate" to create strong immune responses, with the additional benefit of not generating autoimmune-related pathologies.
When they tested their vaccine in mice with HPV16-induced tumors, they found that TriVax containing a small synthetic fragment (peptide) of the E7 protein "induced tumor clearance in 100 percent of the treated mice" while the unvaccinated mice with HPV-induced tumors had their tumors grow "at a fast rate."
"Although the magnitude of the T-cell responses achieved with TriVax in mice is impressive," Barrios-Marrugo said," we do not know whether similar effects can be accomplished in humans."
Celis and Barrios-Marrugo point out that current therapies for cervical cancer can be devastating, highly toxic and associated with a 10 percent chance of recurrence. Additionally, a significant proportion of women in the Third World will not receive the approved prophylactic vaccine to prevent HPV infection and, thus, will continue at high risk for cervical and other cancers related to HPV.
Read more at Science Daily
The research was published in a recent issue of Cancer Immunology, Immunotherapy.
"Vaccines for cancer can be good alternatives to conventional therapies that result in serious side-effects and are rarely effective against advanced disease," said Esteban Celis, M.D., Ph.D., senior member and professor in Moffitt's Immunology Program. "The human papillomavirus, or HPV, is known to cause 99 percent of cervical cancers and annually causes more than 250,000 deaths worldwide." In addition, HPV is the causative agent of a large proportion of head and neck and genital cancers.
Although two approved prophylactic vaccines against strains of HPV that cause cervical cancer are now in wide use as a measure to prevent HPV infections, these vaccines cannot be used to treat HPV-induced cancers. Thus, there is a need to develop therapeutic vaccines for HPV-related tumors.
In an effort to find an effective HPV-cancer vaccine that would eliminate existing HPV-induced cancer, Celis and Kelly Barrios-Marrugo, Ph.D., of the University of South Florida College of Medicine's Molecular Medicine program, designed a peptide vaccination strategy called TriVax-HPV.
The TriVax vaccine strategy was designed to generate large numbers of cytotoxic T-cells that would seek out the proteins preferentially expressed in the tumors. The HPV16-E6 and E7 proteins function as oncogenic proteins inducing cancer. Thus, according to Celis and Barrios-Marrugo, a vaccine targeting these viral proteins is an "ideal candidate" to create strong immune responses, with the additional benefit of not generating autoimmune-related pathologies.
When they tested their vaccine in mice with HPV16-induced tumors, they found that TriVax containing a small synthetic fragment (peptide) of the E7 protein "induced tumor clearance in 100 percent of the treated mice" while the unvaccinated mice with HPV-induced tumors had their tumors grow "at a fast rate."
"Although the magnitude of the T-cell responses achieved with TriVax in mice is impressive," Barrios-Marrugo said," we do not know whether similar effects can be accomplished in humans."
Celis and Barrios-Marrugo point out that current therapies for cervical cancer can be devastating, highly toxic and associated with a 10 percent chance of recurrence. Additionally, a significant proportion of women in the Third World will not receive the approved prophylactic vaccine to prevent HPV infection and, thus, will continue at high risk for cervical and other cancers related to HPV.
Read more at Science Daily
Microbes Discovered in Extreme Environment On South American Volcanoes
A new DNA analysis of rocky soils in the Martian-like landscape on some volcanoes in South America has revealed a handful of bacteria, fungi and other rudimentary organisms called archaea, which seem to have a different way of converting energy than their cousins elsewhere in the world.
"We haven't formally identified or characterized the species," said Ryan Lynch, a CU-Boulder doctoral student involved in the study. "But these are very different than anything else that has been cultured. Genetically, they're at least 5 percent different than anything else in the DNA database of 2.5 million sequences."
Life gets little encouragement on the incredibly dry slopes of the tallest volcanoes in the Atacama region, where CU-Boulder Professor Steve Schmidt and his team collected soil samples. Much of the sparse snow that falls on the terrain sublimates back to the atmosphere soon after it hits the ground, and the soil is so depleted of nutrients that nitrogen levels in the scientists' samples were below detection limits.
Ultraviolet radiation in the high-altitude environment can be twice as intense as in a low-elevation desert, said Schmidt of CU-Boulder's ecology and evolutionary biology department. While the researchers were on site, temperatures dropped to 14 degrees Fahrenheit one night and spiked to 133 F the next day.
How the newfound organisms survive under such circumstances remains a mystery. Although Ryan, Schmidt and their colleagues looked for genes known to be involved in photosynthesis and peered into the cells using fluorescent techniques to look for chlorophyll, they couldn't find evidence that the microbes were photosynthetic.
Instead, they think the microbes might slowly generate energy by means of chemical reactions that extract energy and carbon from wisps of gases such as carbon monoxide and dimethylsulfide that blow into the desolate mountain area. The process wouldn't give the bugs a high-energy yield, Lynch said, but it could be enough as it adds up over time. A paper on the findings has been accepted by the Journal of Geophysical Research-Biogeosciences, published by the American Geophysical Union.
While normal soil has thousands of microbial species in just a gram of soil, and garden soils even more, remarkably few species have made their home in the barren Atacama mountain soil, the new research suggests. "To find a community dominated by less than 20 species is pretty amazing for a soil microbiologist," Schmidt said.
He has studied sites in the Peruvian Andes where, four years after a glacier retreats, there are thriving, diverse microbe communities. But on these volcanoes on the Chile-Argentina border, which rise to altitudes of more than 19,685 feet and which have been ice-free for 48,000 years, the bacterial and fungal ecosystems have not undergone succession to more diverse communities. "It's mostly due to the lack of water, we think," he said. "Without water, you're not going to develop a complex community."
"Overall, there was a good bit lower diversity in the Atacama samples than you would find in most soils, including other mountainous mineral soils," Lynch said. That makes the Atacama microbes very unusual, he added. They probably had to adapt to the extremely harsh environment, or may have evolved in different directions than similar organisms elsewhere due to long-term geographic isolation.
Growth on the mountain might be intermittent, Schmidt suggested, especially if soils only have water for a short time after snowfall. In those situations, there could be microbes that grow when it snows, then fall dormant, perhaps for years, before they grow again. High-elevation sites are great places to study simple microbial communities, ecosystems that haven't evolved past the very basics of a few bacteria and fungi, Schmidt said.
"There are a lot of areas in the world that haven't been studied from a microbial perspective, and this is one of the main ones," he said. "We're interested in discovering new forms of life, and describing what those organisms are doing, how they make a living."
Schmidt's lab, along with others, is studying how microorganisms travel from one site to another. One common method of microbe transport is through the air -- they're caught up in winds, sucked up into clouds, form rain droplets and then fall back to the ground somewhere else as precipitation.
But on mountains like Volcán Llullaillaco and Volcán Socompa, the high UV radiation and extreme temperatures make the landscape inhospitable to outside microbes. "This environment is so restrictive, most of those things that are raining down are killed immediately," Schmidt said. "There's a huge environmental filter here that's keeping most of these things from growing."
The next steps for the researchers are laboratory experiments using an incubator that can mimic the extreme temperature fluctuations to better understand how any organism can live in such an unfriendly environment. Studying the microbes and finding out how they can live at such an extreme can help set boundaries for life on Earth, Schmidt said, and tells scientists what life can stand. There's a possibility that some of the extremophiles might utilize completely new forms of metabolism, converting energy in a novel way.
Schmidt also is working with astrobiologists to model what past conditions were like on Mars. With their rocky terrain, thin atmosphere and high radiation, the Atacama volcanoes are some of the most similar places on Earth to the Red Planet.
"If we know, on Earth, what the outer limits for life were, and they know what the paleoclimates on Mars were like, we may have a better idea of what could have lived there," he said.
Read more at Science Daily
Subscribe to:
Posts (Atom)