For bats, that's a long time to deal with a parasite doing its best vampire impression. Maybe it is nature's revenge on the vampire bat, an aggressive blood consumer in its own right that will feed on anything from sheep to dogs and humans.

The find was made by researchers from Oregon State University in amber from the Dominican Republic that was formed 20-30 million years ago. The bat fly was entombed and perfectly preserved for all that time in what was then oozing tree sap and later became a semi-precious stone.

This is the only fossil ever found of a bat fly, and scientists say it's an extraordinary discovery. It was also carrying malaria, further evidence of the long time that malaria has been prevalent in the New World. The genus of bat fly discovered in this research is now extinct.

The findings have been published in two professional journals, Systematic Parasitology and Parasites and Vectors.

"Bat flies are a remarkable case of specific evolution, animals that have co-evolved with bats and are found nowhere else," said George Poinar, Jr., an OSU professor of zoology and one of the world's leading experts on the study of ancient ecosystems through plants and animals preserved in amber.

"Bats are mammals that go back about 50 million years, the only true flying mammal, and the earliest species had claws and climbed trees," Poinar said.

"We now know that bat flies have been parasitizing them for at least half that time, and they are found exclusively in their fur. They are somewhat flat-sided like a flea, allowing them to move more easily through bat fur."

Not every bat is infested with bat flies, and some of the contemporary flies are specific to certain species of bats. But they are still pretty common and found around the world.

Bat flies only leave their bat in order to mate, Poinar said, and that's probably what this specimen was doing when it got stuck in some sticky, oozing sap.

]]> Thu, 09 FEB 2012 09:07:34 AEST Cincinnati OH (SPX) Feb 08, 2012 - A painstakingly detailed investigation shows that mass extinctions need not be sudden events. The deadliest mass extinction of all took a long time to kill 90 percent of Earth's marine life, and it killed in stages, according to a newly published report.

Thomas J. Algeo, professor of geology at the University of Cincinnati, worked with 13 co-authors to produce a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. Their analysis, published Feb. 3 in the Geological Society of America Bulletin, provides strong evidence that Earth's biggest mass extinction phased in over hundreds of thousands of years.

About 252 million years ago, at the end of the Permian period, Earth almost became a lifeless planet. Around 90 percent of all living species disappeared then, in what scientists have called "The Great Dying." Algeo and colleagues have spent much of the past decade investigating the chemical evidence buried in rocks formed during this major extinction.

The world revealed by their research is horrific and alien: a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge "dead zones" in the oceans, and runaway greenhouse warming leading to sizzling temperatures.

The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia. A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. And the lava flowed where it could most endanger life, through a large coal deposit.

"The eruption released lots of methane when it burned through the coal," he said. "Methane is 30 times more effective as a greenhouse gas than carbon dioxide. We're not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years."

A lot of the evidence ended up being washed into the ocean, and it is among fossilized marine deposits that Algeo and his colleagues look for it. Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a kind of precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.

"In shallow marine deposits, the latest Permian mass extinction was generally abrupt," Algeo said. "Based on such observations, it has been widely inferred that the extinction was a globally synchronous event."

Recent studies are starting to challenge that view.

Algeo and his co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic. That location, at the end of the Permian, would have been a lot closer to the Siberian volcanoes than sites in South China.

The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon. The investigators looked at how the type of rock changed from the bottom to the top of the section. They looked at the chemistry of the rocks. They looked at the fossils contained in the rocks.

They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marinemass extinction event recorded at Tethyan sites. Chemical clues, Algeo said, confirm that life on land was in crisis. Dying plants and eroding soil were being flushed into the ocean where the over-abundant nutrients led to a microbial feeding frenzy and the removal of oxygen - and life - from the late Permian ocean.

What appears to have happened, according to Algeo and his colleagues, is that the effects of early Siberian volcanic activity, such as toxic gases and ash, were confined to the northern latitudes. Only after the eruptions were in full swing did the effects reach the tropical latitudes of the Tethys Ocean.

The research was supported by the National Science Foundation, Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.

]]> Thu, 09 FEB 2012 09:07:34 AEST Washington (AFP) Feb 6, 2012 - The call of a Jurassic-era cricket was simple, pure and capable of traveling long distances in the night, said scientists who reconstructed the creature's love song from a 165 million year old fossil.

British scientists based their work out Monday on an extremely well preserved fossil of a katydid, or bush cricket, from China named Archaboilus musicus. The cricket lived in an era when dinosaurs roamed the earth.

The detailed wings, measuring about 72 centimeters (three-quarters of an inch) long, allowed scientists to recreate for the first time the features that would have produced sound when rubbed together.

The result is "possibly the most ancient known musical song documented to date," said the study which appears in the US journal the Proceedings of the National Academy of Sciences.

The ancient katydid's call should be imagined against a busy backdrop of waterfalls, wind, the sound of water coursing through streams and other amphibians and insects serenading would-be mates, the study authors said.

"This Jurassic bush cricket... helps us learn a little more about the ambiance of a world long gone," said co-author Fernando Montealegre-Zapata of the University of Bristol.

A simple call may have been the creature's best shot at attracting a mate in the nighttime forest, said co-author Daniel Robert, an expert in the biomechanics of singing and hearing in insects at the University of Bristol.

"Singing loud and clear advertises the presence, location and quality of the singer, a message that females choose to respond to -- or not," he said.

"Using a single tone, the male's call carries further and better, and therefore is likely to serenade more females."

However, the long-extinct katydid may have been alerting predators to his location, too. Some 100 million years later, insects began developing the ability to make sounds at frequencies their enemies, like bats, could not hear.

A recreation of the cricket's call can be heard at https://fluff.bris.ac.uk/fluff/u/inxhj/fqxIALCbZk8r_RBMfny__QRy/.

]]> Thu, 09 FEB 2012 09:07:34 AEST Munich, Germany (SPX) Jan 30, 2012 - Kimberlites are magmatic rocks that form deep in the Earth's interior and are brought to the surface by volcanic eruptions. On their turbulent journey upwards magmas assimilate other types of minerals, collectively referred to as xenoliths (Greek for "foreign rocks").

The xenoliths found in kimberlite include diamonds, and the vast majority of the diamonds mined in the world today is found in kimberlite ores. Exactly how kimberlites acquire the necessary buoyancy for their long ascent through the Earth's crust has, however, been something of a mystery.

An international research team led by Professor Donald Dingwell, Director of the Department of Geo- and Environmental Sciences at LMU, has now demonstrated that assimilated rocks picked up along the way are responsible for the providing the required impetus. The primordial magma is basic, but the incorporation of silicate minerals encountered during its ascent makes the melt more acidic.

This leads to the release of carbon dioxide in the form of bubbles, which reduce the density of the melt, essentially causing it to foam.

The net result is an increase in the buoyancy of the magma, which facilitates its continued ascent. "Because our results enhance our understanding of the genesis of kimberlite, they will be useful in the search for new diamond-bearing ores and will facilitate the evaluation of existing sources," says Dingwell. (Nature 18. January 2012)

Most known kimberlites formed in the period between 70 and 150 million years ago, but some are over 1200 million years old. Generally speaking, kimberlites are found only in cratons, the oldest surviving areas of continental crust, which form the nuclei of continental landmasses and have remained virtually unchanged since their formation eons ago.

Kimberlitic magmas form about 150 km below the Earth's surface, i.e. at much greater depths than any other volcanic rocks. The temperatures and pressures at such depths are so high that carbon can crystallize in the form of diamonds.

When kimberlitic magmas are forced through long chimneys of volcanic origin called pipes, like the water in a hose when the nozzle is narrowed, their velocity markedly increases and the emplaced diamonds are transported upwards as if they were in an elevator.

This is why kimberlite pipes are the sites of most of the world's diamond mines. But diamonds are not the only passengers. Kimberlites also carry many other types of rock with them on their long journey into the light.

In spite of this "extra load", kimberlite magmas travel fast, and emerge onto the Earth's surface in explosive eruptions.

"It is generally assumed that volatile gases such as carbon dioxide and water vapour play an essential role in providing the necessary buoyancy to power the rapid rise of kimberlite magmas," says Dingwell, "but it was not clear how these gases form in the magma."

With the help of laboratory experiments carried out at appropriately high temperatures, Dingwell's team was able to show that the assimilated xenoliths play an important role in the process.

The primordial magma deep in the Earth's interior is referred to as basic because it mainly consists of carbonate-bearing components, which may also contain a high proportion of water. When the rising magma comes into contact with silicate-rich rocks, they are effectively dissolved in the molten phase, which acidifies the melt.

As more silicates are incorporated, the saturation level of carbon dioxide dissolved in the melt progressively increases as carbon dioxide solubility decreases.

When the melt becomes saturated, the excess carbon dioxide forms bubbles. "The result is a continuous foaming of the magma, which may reduce its viscosity and certainly imparts the buoyancy necessary to power its very vehement eruption onto the Earth's surface," as Dingwell explains.

The faster the magma rises, the more silicates are entrained in the flow, and the greater the concentration of dissolved silicates - until finally the amounts of carbon dioxide and water vapor released thrust the hot melt upward with great force, like a rocket.

The new findings also explain why kimberlites are found only in ancient continental nuclei. Only here is the crust sufficiently rich in silica-rich minerals to drive their ascent and, moreover, cratonic crust is exceptionally thick.

This means that the journey to the surface is correspondingly longer, and the rising magma has plenty of opportunity to come into contact with silicate-rich minerals.

The project was funded by a European Research Council (ERC) Advanced Investigator Grant (EVOKES) and further supported by an LMUexcellent Research Professorship awarded to Donald Dingwell. (god/PH)

Kimberlite ascent by assimilation-fuelled buoyancy; J.K. Russell, L.A. Porritt, Y. Lavallee, D.B. Dingwell; Nature Advanced Online Publication 18. January 2012; doi: 10.1038/nature10740

]]> Thu, 09 FEB 2012 09:07:34 AEST Providence RI (SPX) Jan 27, 2012 - Since its discovery 150 years ago, scientists have puzzled over whether the winged dinosaur Archaeopteryx represents the missing link in birds' evolution to powered flight. Much of the debate has focused on the iconic creature's wings and the mystery of whether - and how well - it could fly.

Some secrets have been revealed by an international team of researchers led by Brown University. Through a novel analytic approach, the researchers have determined that a well-preserved feather on the raven-sized dinosaur's wing was black. The color and parts of cells that would have supplied pigment are evidence the wing feathers were rigid and durable, traits that would have helped Archaeopteryx to fly.

The team also learned from its examination that Archaeopteryx's feather structure is identical to that of living birds, a discovery that shows modern wing feathers had evolved as early as 150 million years ago in the Jurassic period.

The study, which appears in Nature Communications, was funded by the National Geographic Society and the U.S. Air Force Office of Scientific Research.

"If Archaeopteryx was flapping or gliding, the presence of melanosomes [pigment-producing parts of a cell] would have given the feathers additional structural support," said Ryan Carney, an evolutionary biologist at Brown and the paper's lead author. "This would have been advantageous during this early evolutionary stage of dinosaur flight."

The Archaeopteryx feather was discovered in a limestone deposit in Germany in 1861, a few years after the publication of Charles Darwin's On the Origin of Species. Paleontologists have long been excited about the fossil and other Archaeopteryx specimens, thinking they place the dinosaur at the base of the bird evolutionary tree.

The traits that make Archaeopteryx an evolutionary intermediate between dinosaurs and birds, scientists say, are the combination of reptilian features (teeth, clawed fingers, and a bony tail) and avian features (feathered wings and a wishbone).

The lack of knowledge of Archaeopteryx's feather structure and color bedeviled scientists. Carney, with researchers from Yale University, the University of Akron, and the Carl Zeiss laboratory in Germany, analyzed the feather and discovered that it is a covert, so named because these feathers cover the primary and secondary wing feathers birds use in flight.

After two unsuccessful attempts to image the melanosomes, the group tried a more powerful type of scanning electron microscope at Zeiss, where the group located patches of hundreds of the structures still encased in the fossilized feather.

"The third time was the charm, and we finally found the keys to unlocking the feather's original color, hidden in the rock for the past 150 million years," said Carney, a graduate student in the Department of Ecology and Evolutionary Biology, studying with Stephen Gatesy.

Melanosomes had long been known to be present in other fossil feathers, but had been misidentified as bacteria. In 2006, coauthor Jakob Vinther, then a graduate student at Yale, discovered melanin preserved in the ink sac of a fossilized squid.

"This made me think that melanin could be fossilized in many other fossils such as feathers," said Vinther, now a postdoctoral researcher at the University of Texas-Austin. "I realized that I had opened a whole new chapter of what we can do to understand the nature of extinct feathered dinosaurs and birds."

The team measured the length and width of the sausage-shaped melanosomes, roughly 1 micron long and 250 nanometers wide. To determine the melanosome's color, Akron researchers Matthew Shawkey and Liliana D'Alba statistically compared Archaeopteryx's melanosomes with those found in 87 species of living birds, representing four feather classes: black, gray, brown, and a type found in penguins.

"What we found was that the feather was predicted to be black with 95 percent certainty," Carney said.

Next, the team sought to better define the melanosomes' structure. For that, they examined the fossilized barbules - tiny, rib-like appendages that overlap and interlock like zippers to give a feather rigidity and strength. The barbules and the alignment of melanosomes within them, Carney said, are identical to those found in modern birds.

What the pigment was used for is less clear. The black color of the Archaeopteryx wing feather may have served to regulate body temperature, act as camouflage or be employed for display. But it could have been for flight, too.

"We can't say it's proof that Archaeopteryx was a flier. But what we can say is that in modern bird feathers, these melanosomes provide additional strength and resistance to abrasion from flight, which is why wing feathers and their tips are the most likely areas to be pigmented," Carney said.

"With Archaeopteryx, as with birds today, the melanosomes we found would have provided similar structural advantages, regardless of whether the pigmentation initially evolved for another purpose."

Contributing authors include Vinther, Shawkey, D'Alba, and Jorg Ackermann from Carl Zeiss.

]]> Thu, 09 FEB 2012 09:07:34 AEST Witwatersrand, South Africa (SPX) Jan 26, 2012 - An excavation at a site in South Africa has unearthed the 190-million-year-old dinosaur nesting site of the prosauropod dinosaur Massospondylus - revealing significant clues about the evolution of complex reproductive behaviour in early dinosaurs.

A new study, entitled Oldest known dinosaurian nesting site and reproductive biology of the Early Jurassic sauropodomorph Massospondylus and published in the prestigious international journal Proceedings of the National Academy of Sciences (PNAS), was led by Canadian palaeontologist Prof. Robert Reisz, a professor of biology at the University of Toronto at Mississauga, and co-authored by Drs. Hans-Dieter Sues (Smithsonian Institute, USA), Eric Roberts (James Cook University, Australia), and Adam Yates (Bernard Price Institute (BPI) for Palaeontological Research at Wits).

The study reveals clutches of eggs, many with embryos, as well as tiny dinosaur footprints, providing the oldest known evidence that the hatchlings remained at the nesting site long enough to at least double in size.

Prof. Bruce Rubidge, Director of the BPI at Wits, says: "This research project, which has been ongoing since 2005 continues to produce groundbreaking results and excavations continue. First it was the oldest dinosaur eggs and embryos, now it is the oldest evidence of dinosaur nesting behaviour."

The authors say the newly unearthed dinosaur nesting ground is more than 100 million years older than previously known nesting sites.

At least ten nests have been discovered at several levels at this site, each with up to 34 round eggs in tightly clustered clutches. The distribution of the nests in the sediments indicate that these early dinosaurs returned repeatedly (nesting site fidelity) to this site, and likely assembled in groups (colonial nesting) to lay their eggs, the oldest known evidence of such behaviour in the fossil record.

The large size of the mother, at six metres in length, the small size of the eggs, about six to seven centimetres in diameter, and the highly organised nature of the nest, suggest that the mother may have arranged them carefully after she laid them.

"The eggs, embryos, and nests come from the rocks of a nearly vertical road cut only 25 metres long," says Reisz. "Even so, we found ten nests, suggesting that there are a lot more nests in the cliff, still covered by tons of rock. We predict that many more nests will be eroded out in time, as natural weathering processes continue."

The fossils were found in sedimentary rocks from the Early Jurassic Period in the Golden Gate Highlands National Park in South Africa. This site has previously yielded the oldest known embryos belonging to Massospondylus, a relative of the giant, long-necked sauropods of the Jurassic and Cretaceous periods.

"Even though the fossil record of dinosaurs is extensive, we actually have very little fossil information about their reproductive biology, particularly for early dinosaurs," says David Evans, a University of Toronto at Mississauga alumnus and a curator of Vertebrate Palaeontology at the Royal Ontario Museum.

"This amazing series of 190 million year old nests gives us the first detailed look at dinosaur reproduction early in their evolutionary history, and documents the antiquity of nesting strategies that are only known much later in the dinosaur record," says Evans.

]]> Thu, 09 FEB 2012 09:07:34 AEST Townsville, Australia (SPX) Jan 25, 2012 - Lessons from tens of millions of years ago are pointing to new ways to save and protect today's coral reefs and their myriad of beautiful and many-hued fishes at a time of huge change in the Earth's systems.

The complex relationship we see today between fishes and corals developed relatively recently in geological terms - and is a major factor in shielding reef species from extinction, says Professor David Bellwood of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

"Our latest research provides strong evidence for a view that today's coral hotspots are both a refuge for old species and a cradle for new ones," said Peter Cowman, lead author of a recent report. "This is the first real inkling we've had that just protecting a large area of reef may not be enough - you have to protect the right sorts of reef."

Early coral reefs, 300-400 million years ago were much simpler affairs than today's colourful and complex systems, Prof. Bellwood says. The fish were not specialised to live on or among corals - either lacking jaws altogether, or else feeding on detritus on the seabed or preying on one another.

"By 200 million years ago we are starting to see fish with jaws capable of feeding on corals, but the real explosion in reef diversity doesn't occur till about 50 million years ago when we see fishes very like today's specialist coral feeders emerging."

It is the ever-increasing complexity of this relationship between corals and fishes over the last 20 or 30 million years that produces the wondrous diversity of today's reefs, he says. Each has become more critical to the survival of the other as their lives have become more interwoven.

"When people think of coral reefs, they usually think of the beautiful branching corals like staghorn (Acropora) - well the evidence is now fairly clear that Acropora needs certain fish for it to flourish. But, it now appears that this may be a reciprocal relationship with Acropora being important for the evolution and survival of fishes on coral reefs. "

Unfortunately Acropora corals are highly vulnerable to external impacts like Crown-of-Thorns starfish, coral bleaching, climate change and ocean acidification. Their demise will have far reaching effects on the fishes which interact with them, such as damsels, butterfly fish, cardinals and wrasses.

"The study of the past tells us that reefs are all about relationships and, like a family, for them to survive those relationships need to remain strong," Peter Cowman said.

"In coming years it is probable reefs will be subject to relentless presses that may cause them to change fundamentally. Those with the best long-term prospects of survival will be the ones where the relationships between fish and corals are healthiest.

Both fish and corals managed somehow to survive the five great mass extinction events of the past, though they sustained massive loss of species. Over time these have left us with a world focus of reef biodiversity centered on the Coral Triangle region to Australia's north, which in turn helps recharge Australian coral reefs, especially in the west.

"The Coral Triangle is currently subject to intensifying human and ecosystem pressure. The latest work by Peter Cowman and Prof Bellwood suggests it is both a cradle for new species and a refuge in troubled times - so it is vital that it remain intact.

"This isn't about saving individual species or particular reefs, it's about maintaining the basic relationships which ensure the survival of the whole," says Prof Bellwood.

"We've had a 'heads up' from the past that is giving us fresh insights into what is most important on reefs and why we must protect our precious reefs and fishes into the future."

Their paper "Coral reefs as drivers of cladogenesis: expanding coral reefs, cryptic extinction events, and the development of biodiversity hotspots" by Peter F. Cowman and David R. Bellwood was published in the Journal of Evolutionary Biology 24: 2543-2562. DOI 10.1111/j.1420-9101.2011.02391.x

]]> Thu, 09 FEB 2012 09:07:34 AEST Tokyo, Japan (SPX) Jan 24, 2012 - Researchers at the RIKEN SPring-8 Center in Harima, Japan have clarified the crystal structure of quinol dependent nitric oxide reductase (qNOR), a bacterial enzyme that offers clues on the origins of our earliest oxygen-breathing ancestors.

In addition to their importance to fundamental science, the findings provide key insights into the production of nitrogen oxide, an ozone-depleting and greenhouse gas hundreds of times more potent than carbon dioxide.

As the central process by which cells capture and store the chemical energy they need to survive, cellular respiration is essential to all life on this planet.

While most of us are familiar with one form of respiration, whereby oxygen is used to transform nutrients into molecules of adenosine triphosphate (ATP) for use as energy ("aerobic respiration"), many of the world's organisms breathe in a different way.

At the bottom of the ocean and in other places with no oxygen, organisms get their energy instead using substances such as nitrate or sulfur to synthesize ATP, much the way organisms did many billions of years ago ("anaerobic respiration").

While less well-known, this latter type of cellular respiration is no less important, fuelling the production of most of the world's nitrous oxide (N2O), an ozone depleting and greenhouse gas 310 times more potent than carbon dioxide.

As the enzyme responsible for catalyzing the reactions underlying anaerobic respiration, nitric oxide reductase (NOR) has attracted increasing attention in environmental circles.

The mystery of NOR's catalyzing mechanism, however - which accounts for a staggering 70% of the planet's N2O production - remains largely unsolved.

With their latest research, the team sought an answer to this mystery in the origin of an evolutionary innovation known as the "proton pump".

To accelerate ATP-synthesis, aerobic organisms harness the potential of an electrochemical concentration gradient across the cell, created by "pumping" protons out using energy from an oxygen reduction reaction.

The enzyme powering this mechanism, cytochrome oxidase (COX), is genetically and structurally similar to NOR, suggesting a common ancestor. No evidence of any "pump", however, has been detected in anaerobic organisms.

That is, until now. Using radiation from the RIKEN SPring-8 facility in Harima, Japan, the world's largest synchrotron radiation facility, the researchers probed the 3D structure of qNOR and discovered a channel acting as a proton transfer pathway for a key catalytic reaction.

While not itself a proton pump, the position and function of this pathway suggest it is an ancestor of the proton pump found in COX.

The finding thus establishes first-ever evidence for a proton pump in anaerobic organisms, shedding light onto the mysterious mechanisms governing the production of nitrogen oxide and the evolutionary path that led to their emergence.

]]> Thu, 09 FEB 2012 09:07:34 AEST Moffett Field CA (SPX) Jan 23, 2012 - The saltiness of our blood is often cited as evidence that life originated in the ocean. However, some researchers contend that the first chemical steps toward biology would have been easier in freshwater rather than saltwater.

The exact location for the origin of life is still a wide open question, but many scientists have assumed that it happened somewhere in the ocean.

"The main argument for a marine origin is that there is so much seawater," says David Deamer of UC Santa Cruz. Roughly 98% of the Earth's water bodies are salty, and this percentage was likely much higher 4 billion years ago when we think the first life-forms made their appearance.

But Deamer doesn't think quantity is a substitute for quality. Seawater, in his estimation, is too reactive with certain biomolecules to have served as the "broth" for the primordial soup.

A freshwater origin seems to have been what Charles Darwin was proposing when he imagined the spontaneous formation of biomolecules in "some warm little pond." Deamer and his colleagues are testing Darwin's idea, but with the temperature turned up. They have gone to several geothermally heated "ponds" around the world to see if they can't cook up some of the more complex molecules of life in these freshwater environments. Deamer recounts these adventures in a new book called "First Life: Discovering the Connections between Stars, Cells, and How Life Began."

His critics might say the work could use a pinch of salt.

The ocean in your veins
It's no accident that our blood is about a quarter as salty as the ocean. This level is tightly regulated by the kidneys. Our cells will die if the salt level in blood and other fluids goes too high or too low.

The normal salt that we are familiar with is sodium chloride (NaCl). In solution, the salt breaks up into ions: specifically positively-charged sodium ions and negatively charged chloride ions. All cells - human and otherwise - spend a great deal of time shuffling these and other ions around. This shuffling is necessary to maintain the fluid pressure inside the cell, but it also creates electric potentials that provide a kind of "battery" for performing certain cellular functions.

"This sort of bioenergy is common to all life forms," says Shiladitya DasSarma of the University of Maryland Biotechnology Institute.

The ubiquity of ion-mediated potentials in cells may be telling us something about where life got started.

"I wouldn't think ions could play such an important role unless they were around in the beginning," he says. DasSarma believes that the first organisms arose in salt water that was perhaps extremely salty. The early ocean was perhaps twice as salty as it is today. Moreover, the ingredients of life may have been concentrated by evaporation in a seaside pool or lagoon, which would have concentrated the salt as well.

Bursting life's bubble
The problem with seawater, according to Deamer, isn't the salt, per se. Seawater also contains other ions, like those of magnesium and calcium, which carry a charge of +2. These so-called divalent ions react unfavorably with certain building blocks of life.

For example, calcium ions readily bind with phosphate, thus making this molecule unavailable for important biological functions, such as energy transfer (in the case of adenosine triphosphate, or ATP) and genetic coding (as part of the backbone of DNA and RNA).

Deamer is especially concerned with the effect that divalent ions have on simple fatty acids. These "soapy" molecules - generically called lipids - line up together to form closed vesicles. Several scientists have theorized that self-forming "bubbles" of this sort might have served as a kind of rudimentary cell membrane for the very first organisms.

However, the simple vesicles can't form in seawater because the divalent ions react with the fatty acids. People with mineral-rich "hard" water in their homes are familiar with this chemistry. Soap products don't lather as well with hard water, which has high concentrations of calcium and magnesium ions that react with the soap molecules to form a solid that we call soap scum.

"Seawater would definitely precipitate fatty acids, preventing membrane formation," says Jack Szostak of Harvard University. "So I agree with Dave Deamer that primitive cells had to live in a fresh water environment. "

Throwing the catalyst out with the seawater
The challenge for Deamer is that those divalent ions are far from a nuisance when it comes to other aspects of biochemistry.

DasSarma points out that divalent magnesium ions are needed for important phosphate chemistry, and calcium ions play a vital role in cellular signaling.

Moreover, "some of those divalent ions are transition metals, which I think of as being involved with ligands in pre-macromolecular catalysis," says Harold Morowitz of George Mason University.

Transition metals are elements (like iron, manganese and nickel) that occupy the middle of the Periodic Table. They trade electrons fairly easily, which makes them good catalysts for driving chemical reactions.

When transition metals combine with small organic molecules called "ligands," they can drive important chemical reactions. Nowadays, this catalysis is done by proteins, but these large molecules are so complex that it's hard to imagine them being around at the dawn of life. Morowitz believes transition metals were necessary to get the biological ball rolling.

Michael Russell from the Jet Propulsion Lab seems to agree: "It is the inorganic elements that bring organic chemistry to life." And he goes on to stress that these elements can only stay in solution in saltwater (with its abundant chloride ions), otherwise they tend to precipitate into solids where they no longer can play their biological roles.

Contrary to Deamer's position, Russell doesn't believe life necessarily needed a lipid vesicle in the beginning. He thinks the prebiotic chemistry could have begun inside tiny pores of rocks. Here, proteins and DNA could have assembled in a closed environment.

"It's the proteins that do the work," Russell says. "The lipids are merely the castle wall."

Membranes-first
Deamer doesn't deny that some of the first biological steps may have occurred inside pores or on the surface of clay minerals. But eventually, organisms freed themselves from these fixed structures and ventured out into open water. And that's when they would need a good "container."

"At some point during its origin, life started using membranes," Deamer says.

As any fish will tell you, there are ways to make membranes that are "salt-proof," but these are complicated structures that need to be synthesized by enzymes or something similar, says Deamer. The far easier route is to use spontaneously forming membranes that work great in freshwater. Even though divalent ions would be scarce in this environment, the first proto-cells could still probably scavenge some if needed.

"I certainly would not claim that life began in distilled water," Deamer says. He believes life would need some ions to get going. "It's just that seawater is too much of a good thing."

So where might early life have found a nice freshwater launching pad? The Earth had no continents 4 billion years ago, as the planet was essentially one big ocean. But geologists believe that there were volcanic islands, like Hawaii and Iceland, which could have trapped fresh rain water in ponds or lakes.

Szostak believes these freshwater bodies could accumulate useful organic molecules (in contrast to the ocean where everything tends to get diluted). Being near volcanoes could have provided heat for creating wet-dry cycles. Experiments have shown that these cycles can concentrate lipid molecules to help them organize into membranes.

Deamer has witnessed first-hand these wet-dry cycles in ponds next to modern-day volcanoes in Kamchatka, Hawaii and California. He and his colleagues went so far as to dump lipid molecules into the ponds to see if they might form membranes "in the wild." The answer was no. The organic material attached itself to clay minerals at the bottom of the ponds (something that wouldn't have likely been a problem on the early Earth).

But these field tests haven't deterred Deamer.

"I've learned from visiting these places what to do to simulate these environments in the lab," he says.

His team has built a "hot pond" simulator. Little vials with freshwater and the basic ingredients of life are heated to above 60 degrees Celsius and routinely re-wetted with "rain water" from a syringe. Recent results have shown that membrane-forming lipids not only form vesicles, but they may help drive DNA replication - something that modern cells need protein enzymes to do.

All the simulations have so far used freshwater, but Deamer says they plan to test saltwater to see how the results change.

The salt habit is hard to break.

]]> Thu, 09 FEB 2012 09:07:34 AEST Bochum, Germany (SPX) Jan 18, 2012 - Two-timing is nothing out of the ordinary for them: for about 100 million years, grass smut fungi have been breeding in a three-gender system. This was discovered by Dr. Ronny Kellner and Prof. Dr. Dominik Begerow of the RUB Geobotany Laboratory in cooperation with colleagues from the Heinrich Heine Universitat in Dusseldorf.

Using genetic analysis, they showed that the structure of the responsible regions in the genome has hardly changed since then. In the journal PLoS Genetics, the team also reports that the fungi in the experiment not only mate within their own species, but also form hybrids with other species - and that after millions of years of separate evolution. "If you look at the time periods, it is almost as if mice could mate with humans" Begerow illustrates.

Gathering and genetically analysing fungi
Grass smut fungi live as parasites on plants such as corn, wheat, and grasses and cause various plant diseases. For the study, the researchers tested 100 species, which they partly gathered themselves in Ecuador, Mexico, or Germany.

For all the species they decoded the area of the genome that contains the genes for pheromone receptors. These make it possible to distinguish one's own species from others. "What makes the work special is the successful synthesis of biodiversity research and functional genetics, which was made possible by the collaboration with Prof. Michael Feldbrugge and with Dr. Evelyn Vollmeister of the University in Dusseldorf" says Kellner.

How genes change over 100 million years
The researchers analysed ten species especially thoroughly using complex sequencing technologies. Instead of the usual 1,000 DNA building blocks (base pairs), they sequenced 20,000 base pairs. "In this way, we were able to gain entirely new insights" explained Begerow.

"Although the actual gene structure has changed little in the last 100 million years, within the structure, the genetic information has changed dramatically. That should really mean that different species can no longer mate with each other".

Mixing with other species
Nevertheless, in the experiment the team proved that grass smut fungi of different species can mate. Now they want to investigate whether this phenomenon also occurs in nature. "This is a fascinating discovery", says Kellner. "The hybrid formation would have far-reaching ecological consequences."

A new species of fungus could, for example, be more harmful than its two predecessor species because it infests several different host plants. Leaps to new hosts would also be conceivable. "It's like in the current debate surrounding the bird flu virus, which could combine with another strain of the virus" explained Begerow.

"Here, new 'super parasites' could emerge whose properties are completely unpredictable. If different species of fungi did actually mate, that would speed up evolution enormously."

Kellner R., Vollmeister E., Feldbrugge M., Begerow D. (2011): Interspecific Sex in grass smuts and the genetic diversity of their pheromone-receptor system, PLoS Genetics, doi:10.1371/journal.pgen.1002436

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