Amazing Science
610.2K views | +384 today
Amazing Science
Amazing science facts - 3D_printing • aging • AI • anthropology • art • astronomy • bigdata • bioinformatics • biology • biotech • chemistry • computers • cosmology • education • environment • evolution • future • genetics • genomics • geosciences • green_energy • history • language • map • material_science • math • med • medicine • microscopy • nanotech • neuroscience • paleontology • photography • photonics • physics • postings • robotics • science • technology • video
Your new post is loading...
Scooped by Dr. Stefan Gruenwald!

Russian scientists find frozen blood in mammoth carcass, boosting their chances of cloning

Russian scientists find frozen blood in mammoth carcass, boosting their chances of cloning | Amazing Science |

Russian scientists claimed Wednesday they have discovered blood in the carcass of a woolly mammoth, adding that the rare find could boost their chances of cloning the prehistoric animal. An expedition led by Russian scientists earlier this month uncovered the well-preserved carcass of a female mammoth on a remote island in the Arctic Ocean.


Semyon Grigoryev, the head of the expedition, said the animal died at the age of around 60 some 10,000 to 15,000 years ago, and that it was the first time that an old female had been found.


But what was more surprising was that the carcass was so well preserved that it still had blood and muscle tissue. "When we broke the ice beneath her stomach, the blood flowed out from there, it was very dark," Grigoryev, who is a scientist at the Yakutsk-based Northeastern Federal University, told AFP.


"This is the most astonishing case in my entire life. How was it possible for it to remain in liquid form? And the muscle tissue is also red, the colour of fresh meat," he added. Grigoryev said that the lower part of the carcass was very well preserved as it ended up in a pool of water that later froze over. The upper part of the body including the back and the head are believed to have been eaten by predators, he added.


"The forelegs and the stomach are well preserved, while the hind part has become a skeleton." The discovery, Grigoryev said, gives new hope to researchers in their quest to bring the woolly mammoth back to life.


"This find gives us a really good chance of finding live cells which can help us implement this project to clone a mammoth," he said. "Previous mammoths just have not had such well-preserved tissue."

Ahmed Atef's comment, May 31, 2013 10:47 AM
i can do this cloning ;)
Scooped by Dr. Stefan Gruenwald!

Charred micro-bunny sculpture shows promise of new 3-D shaping material

Charred micro-bunny sculpture shows promise of new 3-D shaping material | Amazing Science |

Though its surface has been turned to carbon, the bunny-like features can still be easily observed with a microscope. This rabbit sculpture, the size of a typical bacterium, is one of several whimsical shapes created by a team of Japanese scientists using a new material that can be molded into complex, highly conductive 3-D structures with features just a few micrometers across. Combined with state-of-the-art micro-sculpting techniques, the new resin holds promise for making customized electrodes for fuel cells or batteries, as well as biosensor interfaces for medical uses. The research team, which includes physicists and chemists from Yokohama National University, Tokyo Institute of Technology, and the company C-MET, Inc., presents its results in a paper published today in the Optical Society's (OSA) open-access journal Optical Materials Express.


The work opens a door for researchers trying to create conductive materials in almost any complex shape at the microscopic or cellular level. "One of the most promising applications is 3-D microelectrodes that could interface with the brain," says Yuya Daicho, graduate student at Yokohama National University and lead author of the paper. These brain interfaces, rows of needle-shaped electrodes pointing in the same direction like teeth on combs, can send or receive electrical signals from neurons and can be used for deep brain stimulation and other therapeutic interventions to treat disorders such as epilepsy, depression, and Parkinson's disease. "Although current microelectrodes are simple 2-D needle arrays," Daicho says, "our method can provide complex 3-D electrode arrays" in which the needles of a single device have different lengths and tip shapes, giving researchers more flexibility in designing electrodes for specialized purposes. The authors also envision making microscopic 3-D coils for heating applications.


Currently, researchers have access to materials that can be used to make complex 3-D structures. But the commercially available resins that work best with modern 3-D shaping techniques do not respond to carbonization, a necessary part of the electrode preparation process. In this stage, a structure is baked at a temperature high enough to turn its surface to carbon. The process of "carbonizing," or charring, increases the conductivity of the resin and also increases its surface area, both of which make it a good electrode. Unfortunately, this process also destroys the resin's shape; a sphere becomes an unrecognizable charred blob. What researchers needed were new materials that could be crafted using 3-D shaping techniques but that would also survive the charring process.


The Japanese team, led by Daicho and his advisor Shoji Maruo, sought to develop materials that would fit these needs. Trained as a chemist, Daicho developed a light-sensitive resin that included a material called Resorcinol Diglycidyl Ether (RDGE), typically used to dilute other resins but never before used in 3-D sculpting. The new mixture had a unique advantage over other compounds -- it was a liquid, and therefore potentially suitable for manipulation using the preferred 3-D sculpting methods.


Daicho, Maruo, and colleagues tested three different concentrations of RDGE in their new compounds. Though there was shrinkage, the materials held their shapes during the charring process (controlled shrinkage of a microstructure can be a good thing in cases where miniaturization of a structure is desired). The resin with the lowest concentration of RDGE shrank 30 percent, while that with the highest concentration shrank 20 percent.


The researchers also tested their new resin's ability to be manipulated using techniques specifically suited for 3-D shaping. In one technique, called microtransfer molding, the light-sensitive liquid was molded into a desired shape and then hardened by exposure to ultraviolet (UV) light. The other technique, preferred because of its versatility, made use of the liquid resin's property of solidifying when exposed to a laser beam. In this process, called two-photon polymerization, researchers used the laser to "draw" a shape onto the liquid resin and build it up layer by layer. Once the objects were shaped, they were carbonized and viewed with a scanning electron microscope (SEM).


In addition to crafting pyramids and discs, the researchers reproduced the well-known "Stanford bunny," a shape commonly used in 3-D modeling and computer graphics. Maruo says that when he first saw a picture of the rabbit structure taken with the SEM, he was delighted at how well it had held up during the charring process.


"When we got the carbon bunny structure, we were very surprised," Maruo says. It was exciting, he continues, to see that "even with a very simple experimental structure, we could get this complicated 3-D carbon microstructure." The rabbit's shape would be much more difficult, expensive, and time-consuming to create using any of the existing processes compatible with carbonization, he adds.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Lucihormetica luckae: Glowing Roaches Mimic Toxic Beetles

Lucihormetica luckae: Glowing Roaches Mimic Toxic Beetles | Amazing Science |

Many marine creatures use bioluminescence to attract a mate or evade predators, but among land-based species it's much rarer. This makes the potential loss of a light-producing cockroach that lives in treetops in the forests of northern and central South America that much more poignant. In the first formal description of the species, scientists dub the 24-millimeter-long insect (shown in visible light, left, and under fluorescent light, right) Lucihormetica luckae. But maybe the cockroaches weren’t so lucky: The only known specimen of the insect was collected in 1939 on the slopes of Ecuador’s Tungurahua volcano, and the site was damaged when the peak erupted in December 2010. L. luckae and the other 12 species of its genus form one of only three groups of insects that can produce light (fireflies are another). The insect’s light-producing organs—two large, eyelike spots on the roach’s back, and a much smaller dot located just behind one of those spots—are bacteria-filled reservoirs in the insect's exoskeleton. New analyses of the light produced by L. luckaeand its kin reveal it is identical to the light produced by click beetles in the genus Pyrophorus living in the same ecosystems, the researchers will report in a forthcoming issue of Naturwissenschaften. While those click beetles presumably generate light to warn potential predators of the highly toxic compounds they produce, the glowing cockroaches are just faking: They produce no such toxins.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Monarch butterflies seem to remember a mountain that hasn't existed for millennia

Monarch butterflies seem to remember a mountain that hasn't existed for millennia | Amazing Science |

Geology is what we look to when we want enduring monuments. Rock and metal outlast anything made of living tissue. Or do they? In another example of science getting poetic, it seems that a symbol of ephemera — a butterfly — provides evidence of a mountain long turned to dust.


Monarch butterflies are some of the toughest insects in the world. Their migration takes them from southern Canada to central Mexico. The journey is so long and difficult that it outlasts the butterfly's lifetime. Monarchs lay eggs at different stages through the journey. No one generation makes the whole trip.


Along this journey are several sites that have become local treasures and tourist attractions. The monarchs, flying in swarms, group together to rest in small areas, covering the trees like bright orange leaves. But although these sites are the most showy part of the journey, they're not the most amazing.


The amazing part of the journey is the sudden eastward turn that monarchs take over Lake Superior. Monarchs fly over the lake, necessarily, in one unceasing flight. That alone would be difficult, but the monarchs make it tougher by not going directly south. They fly south, and at one point of the lake turn east, fly for a while, and then turn back toward the south. Why?


Biologists, and certain geologists, believe that something was blocking the monarchs' path. They believe that that part of Lake Superior might have once been one of the highest mountains ever to loom over North America. It would have been useless for the monarchs to try to scale it, and wasteful to start climbing it, so all successfully migrating monarchs veered east around it and then headed southward again. They've kept doing that, some say, even after the mountain is long gone.


This puts a new spin on how we look at geology and geography. We think of mountains as structures that are, nearly, ageless. They stand while successive generations of animals change and evolve around them. Perhaps not this time, though. This time, butterflies kept up their same pattern while the world changed under them, the mountain wearing away, or being destroyed. This time, flesh outlasted stone.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

12 disruptive multi-trillion dollar technologies that may transform our daily lives in the near future

12 disruptive multi-trillion dollar technologies that may transform our daily lives in the near future | Amazing Science |

1. Mobile Internet $3.7-10.5 trillion
2. Automation of knowledge work $5.2-6.7 trillion
3. Internet of things $2.7-6.2 trillion
4. Cloud $1.7-6.2 trillion
5. Advanced robotics $1.7-4.5 trillion
6. Autonomous or near-autonomous cars $0.2-1.9 trillion
7. Next generation genomics $0.7-1.6 trillion

No comment yet.
Scooped by Dr. Stefan Gruenwald!

3-Year Search Uncovers Novel Hemorrhagic Fever Virus

3-Year Search Uncovers Novel Hemorrhagic Fever Virus | Amazing Science |

Ebola virus, Marburg virus, Lassa fever, Rift Valley fever, yellow fever, and dengue are well known viruses from four different viral families that can cause hemorrhagic fever. But an international team of researchers report in PLoS Pathogens today that the rhabdovirus family, which typically causes brain swelling or flulike disease, can join the club of hemorrhagic fever agents, which are among the most virulent pathogens known to humans.


Using sophisticated RNA sequencing technology, the researchers discovered evidence that links a rhabdovirus to acute hemorrhagic fever in three people from the village of Mangala between 25 May and 14 June 2009. The first two people afflicted with the frightening disease died. But a third, a male nurse who treated both patients at a health center, survived.


The researchers did not actually isolate a rhabdovirus, but instead plucked out RNA sequences from the surviving man's blood sample and reconstructed what they contend is the genome of the pathogen that caused the disease. "It looks fairly solid," says Thomas Ksiazek, an epidemiologist and virologist who specializes in hemorrhagic disease at the University of Texas Medical Branch in Galveston. "Clearly, they have identified a virus in one of the three patients they describe. But trying to make more out of this is speculative. Is the disease due to the agent? You can speculate all you want, but until you have a virus in hand it's hard to answer that."


Delwart's group randomly amplified genetic material with the polymerase chain reaction, sequenced the products, and then checked what they created against databases of known genomes. "We got one very intriguing read," Delwart says. "It was clearly a rhabdovirus." But his team couldn't amplify any more meaningful sequence, so they passed the sample on to Charles Chiu, head of a viral discovery center at the University of California, San Francisco. Chiu sequenced 140 million fragments of genetic material and then merged related fragments to assemble the genome of the Bas-Congo virus.


Virologist Joseph Fair, who works with Metabiota, says the researchers could not isolate the actual virus because it took so long for the nurse's sample to arrive at a lab that could probe for agents. "We do the best we can with what we have here," Fair says, speaking by phone from Isiro, Congo, where he's working on a new Ebola outbreak. "We're trying to build capacity to build cold chains in cases like this."


Fair points to several lines of evidence that the Bas-Congo virus is real. He notes that the research teams exhaustively searched for other pathogens. "We found nothing except this rhabdovirus," he emphasizes. Based on genomic copies of Bas-Congo virus, the nurse also had high levels of the bug. The researchers then made a lab tool known as a pseudovirus, which contained the surface protein from Bas-Congo inside of a vesicular stomatitis virus, to run a confirmatory antibody test.


Specifically, they showed that antibodies taken from the nurse in January 2012, as well as from an asymptomatic nurse who cared for him, prevented the pseudovirus from infecting cells in a culture dish. Fair and his co-authors also note that another hemorrhagic fever virus, Lujo, was first found in 2009 using similar genetic techniques to those they relied on.


But Fair acknowledges the importance of isolating the virus itself. "Since we weren't able to get an isolate, that limits what we can know about how it kills people and the effect it has on the immune system," Fair says. "Along with our Congolese colleagues, our next step will be to mount an expedition to find this virus."

CineversityTV's curator insight, May 28, 2013 11:22 AM

what we predicted 4 years ago is starting to SARS found also..AIRBORNE VIRUS..

Scooped by Dr. Stefan Gruenwald!

Green Sahara: research points to an abrupt climate shift in the Sahara 5,000 years ago

Green Sahara: research points to an abrupt climate shift in the Sahara 5,000 years ago | Amazing Science |

As recently as 5,000 years ago, the Sahara — today a vast desert in northern Africa, spanning more than 3.5 million square miles — was a verdant landscape, with sprawling vegetation and numerous lakes. Ancient cave paintings in the region depict hippos in watering holes, and roving herds of elephants and giraffes — a vibrant contrast with today’s barren, inhospitable terrain.

The Sahara’s “green” era, known as the African Humid Period, likely lasted from 11,000 to 5,000 years ago, and is thought to have ended abruptly, with the region drying back into desert within a span of one to two centuries. 

Now researchers at MIT, Columbia University and elsewhere have found that this abrupt climate change occurred nearly simultaneously across North Africa. The team traced the region’s wet and dry periods over the past 30,000 years by analyzing sediment samples off the coast of Africa. Such sediments are composed, in part, of dust blown from the continent over thousands of years: The more dust that accumulated in a given period, the drier the continent may have been.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Plants re-grow after five centuries under the ice

Plants re-grow after five centuries under the ice | Amazing Science |

Plants have long been reported to emerge from beneath Arctic glacier ice. One study from 1966 stated that “vigorous new moss shoots appear in places to be growing directly out of the underlying dead moss.” It concluded the new growth was a result of germination of either dormant or migrant spores on the “dead moss mats.”

That and all other publications since then, presumed that the emergent vegetation was dead. Now for the first time, researchers realized that at least part of that re-growth is coming from the Ice Age plants themselves. “This is an important distinction,” explains the lead scientist Dr. Catherine La Farge from University of Alberta.

Emergent population of Aulacomnium turgidum from beneath the Tear Drop Glacier, Sverdrup Pass, Ellesmere Island, Nunavut. Credit: Image courtesy of Catherine La Farge.


To confirm their observations in the field, the team of scientists collected samples of these recently uncovered plants and grew them in the lab under careful monitoring. The results were unprecedented: a third of the plants re-grew! The discovery was reported in Proceeding of the National Academy of Sciences (PNAS).

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Novel aerobic, gram-positive bacterium is able to thrive at - 15˚C - the coldest ever reported to support growth

Novel aerobic, gram-positive bacterium is able to thrive at - 15˚C - the coldest ever reported to support growth | Amazing Science |

Bacterium Planococcus halocryophilus that is able to thrive at minus 15 degrees Celsius offers clues about microbial life on both Mars and Saturn moon Enceladus, where similar briny subzero conditions are thought to exist.

A team from McGill University discovered the bacterium Planococcus halocryophilus OR1 in 2011 after screening about 200 separate High Arctic microbes looking for the microorganism best adapted to the harsh conditions of the Arctic permafrost.


”We believe that this bacterium lives in very thin veins of very salty water found within the frozen permafrost on Ellesmere Island. The salt in the permafrost brine veins keeps the water from freezing at the ambient permafrost temperature (minus 16 degrees Celsius), creating a habitable but very harsh environment. It’s not the easiest place to survive but this organism is capable of remaining active to at least minus 25 degrees Celsius in permafrost,” said Prof Lyle Whyte, senior author of a paper published in the ISME Journal.


In order to understand what it takes to be able to do so, the researchers studied the genomic sequence and other molecular traits of Planococcus halocryophilus OR1. They found that the bacterium adapts to the extremely cold, salty conditions in which it is found thanks to significant modifications in its cell structure and function and increased amounts of cold-adapted proteins. These include changes to the membranes that envelop the bacterium and protect it from the hostile environment in which it lives.


The genome sequence also revealed that Planococcus halocryophilus OR1 is unusual in other ways. It appears to maintain high levels of compounds inside the bacterial cell that act as a sort of molecular antifreeze, keeping the microbe from freezing solid, while at the same time protecting the cell from the very salty exterior environment.


The scientists believe however, that such microbes may potentially play a harmful role in extremely cold environments such as the High Arctic by increasing carbon dioxide emissions from the melting permafrost, one of the results of global warming.


“I’m kind of proud of this bug. It comes from the Canadian High Arctic and is our cold temperature champion, but what we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the Solar System,” Prof Whyte concluded.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Physicists suggest possible existence of other kinds of dark matter

Physicists suggest possible existence of other kinds of dark matter | Amazing Science |

A team of Harvard University physicists has proposed the possible existence of a type of dark matter not described by current physics models. In their paper published in the journal Physical Review Letters, the team suggests it's possible that not all dark matter is cold and collision-less.

In the visible universe, galaxies form into a disk shape—the Milky Way is a good example. All of its members align roughly along a single plane, this due to the forces of gravity and spin. Objects form into masses which, over time, spread out into a disk shape. Dark matter, on the other hand, appears to hover around galaxies like a halo, at least according to current models. It's seen as dark, cold and with so little energy that dark matter particles rarely if ever run into one another. The researchers in this new study suggest there may be other types of matter, however, that behaves more like visible matter. And, because of that, they suggest it could bunch up due to dark-matter-type gravity and form disks as well. These disks, which they describe as dark matter component double-disk dark matter, could represent as much as 5 percent of all existing dark matter.


For dark matter to clump, it would need to have other properties similar to visible matter as well. For that reason, the researchers suggest it's possible that there exists dark atoms, dark photons, and likely some form of dark electromagnetic force as well.


Research on dark matter over the years has led to a model that describes dark matter as existing in a ball shape—galaxies sit in the middle of the ball, which would mean observers living in a galaxy would "see" it as existing everywhere around them. But it's possible that other types of shapes exist as well, the researchers suggest, because there are other types of matter in the visible universe. They note that baryonic matter (matter made of strongly acting fermions known as baryons) is believed to make up approximately 5 percent of all matter in the known universe. For that reason, they conclude that it would appear likely that similar differences in dark matter would occur as well, and perhaps in nearly equal proportions.


If true, it would mean there could be whole dark galaxies out there, undetectable, yet as real as those we can see with the naked eye. Much more research will have to be done in this area before adding such types of dark matter to models in general use, of course. Until then, it will remain an abstract theory.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Detection of the cosmic gamma ray horizon measures all light in the universe since the big bang

Detection of the cosmic gamma ray horizon measures all light in the universe since the big bang | Amazing Science |

How much light has been emitted by all galaxies since the cosmos began? After all, almost every photon (particle of light) from ultraviolet to far infrared wavelengths ever radiated by all galaxies that ever existed throughout cosmic history is still speeding through the Universe today. If we could carefully measure the number and energy (wavelength) of all those photons—not only at the present time, but also back in time—we might learn important secrets about the nature and evolution of the Universe, including how similar or different ancient galaxies were compared to the galaxies we see today. 

That bath of ancient and young photons suffusing the Universe today is called the extragalactic background light (EBL). An accurate measurement of the EBL is as fundamental to cosmology as measuring the heat radiation left over from the Big Bang (the cosmic microwave background) at radio wavelengths. A new paper, called “Detection of the Cosmic γ-Ray Horizon from Multiwavelength Observations of Blazars,” by Alberto Dominguez and six coauthors, just published today by the Astrophysical Journal—based on observations spanning wavelengths from radio waves to very energetic gamma rays, obtained from several NASA spacecraft and several ground-based telescopes—describes the best measurement yet of the evolution of the EBL over the past 5 billion years.

So, astrophysicists developed an ingenious work-around method: measuring the EBL indirectly through measuring the attenuation of—that is, the absorption of—very high energy gamma rays from distant blazars. Blazars are supermassive black holes in the centers of galaxies with brilliant jets directly pointed at us like a flashlight beam. Not all the high-energy gamma rays emitted by a blazar, however, make it all the way across billions of light-years to Earth; some strike a hapless EBL photon along the way. When a high-energy gamma ray photon from a blazar hits a much lower energy EBL photon, both are annihilated and produce two different particles: an electron and its antiparticle, a positron, which fly off into space and are never heard from again. Different energies of the highest-energy gamma rays are waylaid by different energies of EBL photons. Thus, measuring how much gamma rays of different energies are attenuated or weakened from blazars at different distances from Earth indirectly gives a measurement of how many EBL photons of different wavelengths exist along the line of sight from blazar to Earth over those different distances.

Observations of blazars by NASA’s Fermi Gamma Ray Telescope spacecraft for the first time detected that gamma rays from distant blazars are indeed attenuated more than gamma rays from nearby blazars, a result announced on November 30, 2012, in a paper published in Science, as theoretically predicted. 

Now, the big news—announced in today’s Astrophysical Journal paper—is that the evolution of the EBL over the past 5 billion years has been measured for the first time. That’s because looking farther out into the Universe corresponds to looking back in time. Thus, the gamma ray attenuation spectrum from farther distant blazars reveals how the EBL looked at earlier eras. 

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Snapping a picture of the inside of an atom - the internal quantum workings visualized

Snapping a picture of the inside of an atom - the internal quantum workings visualized | Amazing Science |

Physicists have, for the first time, been able to image the quantum workings of electrons in hydrogen atoms, an advance that could open the door to a deeper understanding of the quantum world. Snapping a picture of the inside of an atom - the electrons, the protons, the neutrons - is no easy task. Quantum mechanics makes it virtually impossible to pin down these subatomic particles.


Instead of having the ability to describe where a particle is, quantum theory provides a description of its whereabouts called a wave function.

Wave functions work like sound waves, except that whereas the mathematical description of a sound wave defines the motion of molecules in air at a particular place, a wave function describes the probability of finding the particle.


Physicists can theoretically predict what a wave function is like, but measuring a wave function is very hard because they are exquisitely fragile.


In another bit of quantum weirdness, most attempts to directly observe wave functions actually destroy them in a process called collapse.

So to experimentally measure the properties of a wave function requires researchers to reconstruct it from many separate destructive measurements on identically prepared atoms or molecules.


Physicists at AMOLF, a lab of the Netherlands' Foundation for Fundamental Research on Matter (FOM) in Amsterdam, demonstrated a new nondestructive approach in a paper published in Physical Review Letters.


Building on a 1981 proposal by three Russian theorists and more recent work that brought that proposal into the realm of possibility, the team first fired two lasers at hydrogen atoms inside a chamber, kicking off electrons at speeds and directions that depended on their underlying wave functions. A strong electric field inside the chamber guided the electrons to positions on a planar detector that depended on their initial velocities rather than on their initial positions.


So the distribution of electrons striking the detector matched the wave function the electrons had at the moment they left their hydrogen nuclei behind. The apparatus displays the electron distribution on a phosphorescent screen as light and dark rings, which the team photographed using a high-resolution digital camera.


"We are really happy with our results," said team leader Aneta Stodolna, noting that although quantum mechanics was part of daily life for physicists, it was rarely understood in such a visceral way.


She said that there may be practical applications in the future - a commentary accompanying the paper suggests that the method could aid in the development of technologies such as molecular wires, atom-thick conductors that could help shrink electronic devices - but that their result concerned "extremely fundamental" physics that might be just as valuable for developing quantum intuition in the next generation of physicists.


"It's an interesting experiment, mostly because it's investigating hydrogen," an element that is both a textbook example in undergraduate physics classes and also makes up three-quarters of the universe, said Jeff Lundeen, a physicist at the University of Ottawa in Canada, who has performed related experiments on photon wave functions.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

RNA Interference: Nanocoatings on bandages could deliver RNAs to shut off disease-related genes

RNA Interference: Nanocoatings on bandages could deliver RNAs to shut off disease-related genes | Amazing Science |

Medical researchers think specially tailored RNA sequences could turn off genes in patients’ cells to encourage wound healing or to kill tumor cells. Now researchers have developed a nanocoating for bandages that could deliver these fragile gene-silencing RNAs right where they’re needed (ACS Nano 2013, DOI:10.1021/nn401011n). The team hopes to produce a bandage that shuts down genes standing in the way of healing in chronic wounds.


Small interfering RNAs, or siRNAs, derail expression of specific genes in cells by binding to other RNA molecules that contain the code for those genes. Biologists have developed siRNAs that target disease-related genes. But for these siRNAs to reach the clinic, researchers must find a way to deliver the molecules safely to the right cells. Unfortunately, free oligonucleotides like siRNAs don’t fare well inside the body or cells as enzymes and acids quickly chop them up, says Paula T. Hammond, a chemical engineer at Massachusetts Institute of Technology.


Other groups have tackled this delivery challenge by attaching siRNAs to chemical carriers that protect the oligonucleotides as they travel through the bloodstream. The pharmaceutical company Sanofi-Aventis asked Hammond to design a vehicle that would work at the site of a wound or tumor, releasing the siRNAs over a long period of time. The company hoped that putting the biomolecules right where they’re needed, without them having to survive a trip through the bloodstream, would increase the efficacy of the treatment.


Hammond and her colleagues produced an siRNA-containing nanocoating that could be applied to a wide range of medical materials, such as bandages or biodegradable polymers doctors could implant during surgery to prevent an excised tumor from coming back. As the coating slowly dissolves, it releases siRNA molecules tethered to protective nanoparticles.


The thin films consist of two different materials: a peptide called protamine sulfate and calcium phosphate nanoparticles decorated with the therapeutic siRNAs. Other researchers have shown that similar nanoparticles help the nucleotides evade destruction once they’re taken up by cells (J. Controlled Release 2010, DOI: 10.1016/j.jconrel.2009.11.008).


The team alternately dips whatever they want to coat in water solutions of the two materials. The RNA and nanoparticles are negatively charged, and the peptides are positively charged. The two substances cling together due to electrostatic force, producing a film when the water dries.


To test their delivery method, the researchers coated woven nylon bandages with 80-nm-thick films and applied the bandages to layers of human and animal cells in culture. In one experiment, a bandage loaded with 19 µg of siRNA per square centimeter released two-thirds of its load over 10 days. Other bandages made using siRNAs targeting the gene for fluorescent green protein almost completely shut down the protein’s production in cells expressing the gene. Hammond says the group is now testing bandages that knock down MMP9, a collagen-destroying protein associated with slow healing in chronic wounds.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Is our universe merely one of billions? Evidence of the existence of 'multiverse' revealed for the first time by cosmic map

Is our universe merely one of billions? Evidence of the existence of 'multiverse' revealed for the first time by cosmic map | Amazing Science |

Scientists studying radiation data from the European Space Agency's Planck spacecraft have found unexpected anomalies that they say can only be explained by the existence of other universes and their pull.


The first 'hard evidence' that other universes exist has been found by scientists. Cosmologists studying a map of the universe from data gathered by the Planck spacecraft have concluded that it shows anomalies that can only have been caused by the gravitational pull of other universes. The map shows radiation from the Big Bang 13.8billion years ago that is still detectable in the universe - known as cosmic microwave radiation.

Scientists had predicted that it should be evenly distributed, but the map shows a stronger concentration in the south half of the sky and a 'cold spot' that cannot be explained by current understanding of physics.

Laura Mersini-Houghton, theoretical physicist at the University of North Carolina at Chapel Hill, and Richard Holman, professor at Carnegie Mellon University, predicted that anomalies in radiation existed and were caused by the pull from other universes in 2005.

Now that she has studied the Planck data, Dr. Mersini-Houghton believes her hypothesis has been proven. Her findings imply there could be an infinite number of universes outside of our own. She said: 'These anomalies were caused by other universes pulling on our universe as it formed during the Big Bang. 'They are the first hard evidence for the existence of other universes that we have seen.'


Although some scientists remain sceptical about the theory of other universes, these findings may be a step towards changing views on physics. The European Space Agency, which runs the £515million Planck telescope, said: 'Because precision of Planck’s map is so high, it made it possible to reveal some peculiar unexplained features that may well require new physics to be understood.'

Cambridge professor of theoretical physics Malcolm Perry told the Sunday Times that the findings could be real evidence of the existence of other universes. While George Efstathiou, professor of astrophysics at the university, told the newspaper: 'Such ideas may sound wacky now, just like the Big Bang theory did three generations ago. But then we got evidence and now it has changed the whole way we think about the universe.'

No comment yet.
Scooped by Dr. Stefan Gruenwald!

The tiny insect (Zorotypus impolitus) with the massive 3 mm long single sperm

The tiny insect (Zorotypus impolitus) with the massive 3 mm long single sperm | Amazing Science |

A Malaysian ground louse has a unique mating habit that may illuminate how sex evolved: the males attach an unusual packet of sperm to the females' bodies.


Everything about Z. impolitus mating is strange. The female starts the process, approaching the male and stroking him with her antennae. If the male wants to mate, he moves behind her and performs a simple dance: he walks forwards and backwards, lowers his head and vibrates his antennae.


The climax of the process is when the male slips underneath the female for a few seconds and attaches a spermatophore to the female's abdomen: a tiny package with a large surprise. "It [the sperm package] is the smallest we have seen in all insects," he says. Whereas other species make spermatophores up to 2 millimetres across, those of Z. impolitus are just 0.1 millimetres across.


When Dallai dissected some of these spermatophores, however, he found that each one contained a single sperm about 3 millimetres long – about as long as the female. This seems strange. Males generally want to maximise their chances of fertilising the female's eggs, so why produce only one, giant sperm?


Dallai thinks it may be a way of outcompeting other males. "The sperm is so large, it can fill the space in the female's [genital tract]," he says. That plugs it up, so no other male can mate with her. Also, by using only one sperm at a time, the male ensures he gives each female just enough to fertilize her, while leaving him plenty to fertilize other females.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Hidden alien footprints in Kepler Data? Hunting aliens by searching for megastructures

Hidden alien footprints in Kepler Data? Hunting aliens by searching for megastructures | Amazing Science |

In the search for intelligent extraterrestrials, scientists listen for incoming radio signals and they hunt for Earth-like planets. Some scientists are also looking for megastructures constructed by aliens.

NASA’s Kepler space telescope searches for planets using the transit method–Kepler’s sensors detect dips in brightness caused when an alien planet passes in front of its star from Kepler’s perspective. And this same method is used by scientists searching the universe for alien megastructures.


Astronomer Geoff Marcy, who was recently appointed to the new Watson and Marilyn Alberts Chair for SETI (Search for Extraterrestrial Intelligence) at the University of California at Berkeley, was awarded a grant to hunt for evidence of Dyson spheres using Kepler data. A Dyson sphere is a theoretical megastructure envisioned by theoretical physicist Freeman Dyson consisting of a giant array of solar panels that would surround a star to harvest its energy.


Scientists hunting alien megastructures are also looking for theoretical structures known as ringworlds. Universe Todayexplains that ringworlds “would consist of a giant ring in orbit around a star, constructed comfortably inside the star’s habitable zone.”


Whether alien megastructures actually exist is unknown. But as Universe Today points out, “The possibility alone is exciting enough to make it worth continuing to look.”

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Self-driving car technology that would only add $4000 to price of a car wins INTEL science fair

Self-driving car technology that would only add $4000 to price of a car wins INTEL science fair | Amazing Science |

Ionut Budisteanu, 19, of Romania was awarded first place for using artificial intelligence to create a viable model for a low-cost, self-driving car at this year's Intel International Science and Engineering Fair. His whole system should work for no more $4,000. 

Ionut created a feasible design for an autonomously controlled car that could detect traffic lanes and curbs, along with the real-time position of the car.

"The most expensive thing from the Google self-driving car is the high resolution 3-D radar, so I was thinking how I could remove it," he told NBC News.

His solution relies on processing webcam imagery with artificial intelligence technology to pick out the curbs, lane markers, and even soccer balls that roll onto the road. This is coupled with data from a low-resolution 3-D radar that recognizes "big" objects such as other cars, houses, and trees.

All of this information is collected and processed real time by a suite of computers that, in turn, feed into a "supervisor" computer program that calculates the car's path and drives it down the road.

Budisteanu ran 50 simulations with his system and in 47 of them it performed flawlessly. In three, however, it failed to recognize some people who were 65 to 100 feet (20 to 30 meters) away. He said slightly higher-resolution 3-D radar should do the trick and still keep costs at a fraction of Google's.

The advantages of self-driving cars are many, noted Budisteanu. More than 2 million people die each year in car wrecks. An additional 50 million people are injured in traffic accidents. 87 percent of the car accidents are only because of human mistakes.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

RNA in single cells sequenced and up to 1000-fold variability in transcription levels found

RNA in single cells sequenced and up to 1000-fold variability in transcription levels found | Amazing Science |

A team of scientists at the Klarman Cell Observatory at the Broad Institute recently completed an effort to read, or sequence, all the RNA — the “transcriptome” — in individual immune cells. Whereas DNA in a cell’s genome represents its blueprint for making the building blocks of cells, RNA is more like the cell’s contractor, turning that blueprint into proteins. By sequencing RNA in single cells, scientists can obtain a picture of what proteins each cell is actively making and in what amounts.

The Broad researchers sought to adapt a recently developed technique for single-cell RNA sequencing, known as SMART-Seq, and apply it to a model of immune cell response well-studied by Regev, Broad senior associate member Nir Hacohen, and their fellow researchers. In this model, immune cells known as bone-marrow derived dendritic cells (BMDCs) are exposed to a bacterial cell component that causes the cells to mount an immune response.

Working with scientists in the Broad’s Genomics Platform, notably research scientists Joshua Levin and Xian Adiconis, the team established the SMART-Seq method for use in their model system, using it to gather RNA sequence data from 18 BMDCs in this pilot phase.

The team first analyzed the data for differences in expression, or activity, of various genes among the cells, seen as alterations in RNA abundance. Although they were working with a single cell type — BDMCs — they did expect to see some variation in gene expression as cells activated various pathways during their immune response. But the team discovered that some genes varied greatly, with 1000-fold differences in the expression levels between cells. “We went after a narrowly defined cell type that has a specific function that we think of as being very uniform,” said Shalek. “What we saw was striking — a tremendous variability that wasn’t expected.”

Jeroen Verheyen's curator insight, May 29, 2013 8:38 AM

Even at the bottom, enities are unique! However, to what extend is this a relevant observation? Does "some genes" refer to genes relevant to the triggered immune response or not? Of course one can imagine that one cell can encounter somewhat more or less stress during an assay, giving rise to different expression levels. Also events such as cell-cell contact in vitro can strongly alter gene expression. However, the observation would be very interesting if we could confirm that the the strong variance in expression was induced specifically by the immune trigger. Spatial and temporal variations in triggers could induce different expression patterns in identical cells. Imagine that a BMDC cell n° 1 is the first t encounter the bacterial components. This cell will then undergo changes in its expression levels and produce cytokines (chemical triggers that message to neighbouring cells). Now, cell n° 2 will get challenged with the bacterial components and the cytokines. And maybe cell n° 3 will never get into contact with the bacterial components, and only with the cytokines. Furthermore, at some time at some place, cytokine levels may be so high that a negative feedback loop is induced (for example expression of countering cytokine). So, one can imagine that in this complex temporal and spatial mixture of triggers and messages, every cell will respond somewhat different. It is possible that this differentiation and pattern formation is important to enhance the immune response by creating different cell with different purposes.

Scooped by Dr. Stefan Gruenwald!

Bizarre 6-Inch Skeleton Shown to Be Human

Bizarre 6-Inch Skeleton Shown to Be Human | Amazing Science |

Subhuman primate? Deformed child? Mummified fetus? The Internet is buzzing over the nature of "Ata," a bizarre 6-inch-long skeleton featured in a new documentary on UFOs. A Stanford University scientist who boldly entered the fray has now put to rest doubts about what species Ata belongs to. But the mystery is not over.


The story began 10 years ago, when the diminutive remains were reportedly found in a pouch in a ghost town in the Atacama Desert of Chile. Ata ended up in a private collection in Barcelona; producers of the film Sirius latched onto the bizarre mummy as evidence of alien life.

Last fall, immunologist Garry Nolan, director of the National Heart, Lung, and Blood Institute's Proteomics Center for Systems Immunology at Stanford in California, heard about Ata from a friend and contacted the filmmakers, offering to give them a scientific readout on the specimen. They asked him to give it a shot.


Among the apparent abnormalities, Ata sports 10 ribs instead of the usual 12 and a severely misshapen skull. "I asked our neonatal care unit how you would go about analyzing it. Had they seen this kind of syndrome before?" Nolan says. He was directed to pediatric radiologist Ralph Lachman, co-director of the International Skeletal Dysplasia Registry at Cedars-Sinai Medical Center in Los Angeles, California. "He literally wrote the book on pediatric bone disorders," Nolan says. Lachman was blown away, Nolan recalls: "He said, 'Wow, this is like nothing I've ever seen before.' "


To study the specimen, Nolan sought clues in Ata's genome. He initially presumed the specimen was tens or hundreds of thousands of years old—the Atacama Desert may be the driest spot on the planet, so Ata could have been preserved for eons. He consulted experts who had extracted DNA from bones of the Denisovans, an Asian relative of European Stone Age Neandertals. It turned out that their protocols weren't necessary. "The DNA was modern, abundant, and high quality," he says, indicating that the specimen is probably a few decades old.


To the chagrin of UFO hunters, Ata is decidedly of this world. After mapping more than 500 million reads to a reference human genome, equating to 17.7-fold coverage of the genome, Nolan concluded that Ata "is human, there's no doubt about it." Moreover, the specimen's B2 haplotype—a category of mitochondrial DNA—reveals that its mother was from the west coast of South America: Chile, that is.


Meanwhile, after examining x-rays, Lachman concluded that Aka's skeletal development, based on the density of the epiphyseal plates of the knees (growth plates at the end of long bones found only in children), surprisingly appears to be equivalent to that of a 6- to 8-year-old child. If that holds up, there are two possibilities, Nolan says. One, a long shot, is that Ata had a severe form of dwarfism, was actually born as a tiny human, and lived until that calendar age. To test that hypothesis, he will try to extract hemoglobin from the specimen's bone marrow and compare the relative amounts of fetal versus adult hemoglobin proteins. The second possibility is that Ata, the size of a 22-week-old fetus, suffered from a severe form of a rare rapid aging disease, progeria, and died in the womb or after premature birth.


Nolan hasn't yet turned up hits for genes known to be associated with progeria or dwarfism. He's stepping up the search for mutations through additional sequencing and casting a wider net. Another possibility is a teratogen: a birth defect-inducing toxicant along the lines of thalidomide. Nolan plans to analyze tissue using mass spectrometry to look for toxicants or metabolites. But reports of a handful of other Tom Thumb-sized skeletons from Russia and elsewhere have Nolan leaning toward a genetic explanation.


At least one expert has a more prosaic take—but agrees that the specimen is human. "This looks to me like a badly desiccated and mummified human fetus or premature stillbirth," says William Jungers, a paleoanthropologist and anatomist at Stony Brook University Medical Center in New York. He notes that "barely ossified and immature elements" of the hands and feet, and the wide open metopic suture, where the two frontal bones of the skull come together down the middle of the forehead. "Genetic anomalies are not evident, probably because there aren't any," he says. Nolan responds that the rib number and epiphyseal plate densities remain a riddle; while he is open to the fetus hypothesis, he thinks that the jury is still out.


Nolan's analysis went viral this week; besieged as he has been by the media circus, he doesn't regret having gotten involved in debunking a claim of alien life. "I'm thrilled with the outcome," he says. Once the analyses are complete, he says, he'll submit his findings for peer review. The other claim Nolan debunks is that Ata is an elaborate hoax. The x-rays clearly show these are real bones, complete with arterial shadows, he says. "You just couldn't fake it," he says, adding, with a laugh, "unless you were an alien."

No comment yet.
Scooped by Dr. Stefan Gruenwald!

FGF21 overexpression leads to significant lifespan extension in mice (38 months vs. 28 months)

FGF21 overexpression leads to significant lifespan extension in mice (38 months vs. 28 months) | Amazing Science |

In 1934, in a famous experiment at Cornell University, it was discovered that
laboratory mice could live twice as long as expected if they were fed a low-calorie diet that included enough nutrients to avoid malnutrition. This phenomenon has since been observed in species ranging from worms to primates, but not in humans. Reducing calorie intake leads to longer lives by
modifying a number of the biochemical pathways that sense nutrients, including pathways that involve insulin and various other biomolecules. Chemical and genetic methods can also increase longevity by modifying these pathways, which suggests that it might be possible to develop drugs
that can increase lifespan without reducing calorie intake.

Mice, humans and other creatures respond to prolonged fasting through a number of adaptive changes that include mobilizing and burning fatty acids. The liver has an important role in this response, secreting a hormone called fibroblast growth factor-21 (FGF21) that coordinates these processes among tissues. Previous experiments on transgenic mice with high levels of this hormone have shown that it suppresses the activity of growth hormone and reduces the production of insulin-like growth factor, which prevents growth and can lead to hibernation-like behavior.

Here Zhang et al. from the University of Texas Southwestern Medical Center compare groups of wild-type mice and transgenic mice with high levels of FGF21. They find that the transgenic mice have a longer median survival time than wild-type mice (38 months vs 28 months), and that the transgenic female mice on average live for 4 months longer than their male counterparts. However, unlike in other examples of increased longevity, they find that decreased food intake is not required. Instead, they find that transgenic mice eat more food than wild-type mice, yet remain profoundly insulin-sensitive.


The results suggest that the longer survival times are caused by a reduction in the production of insulin-like growth factor, but they also suggest that the mechanism responsible for the increased longevity is independent of the three pathways that are usually associated with such increases. Further research is needed to understand this mechanism in greater detail and could, perhaps, pave the way for the use of FGF21-based hormone therapy to extend lifespan without the need for a low-calorie diet.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Rats have a double view of the world, presumably for maximum surveillance to protect from predatory birds

Rats have a double view of the world, presumably for maximum surveillance to protect from predatory birds | Amazing Science |

Scientists from the Max Planck Institute for Biological Cybernetics in Tübingen, using miniaturised high-speed cameras and high-speed behavioural tracking, discovered that rats move their eyes in opposite directions in both the horizontal and the vertical plane when running around. Each eye moves in a different direction, depending on the change in the animal’s head position. An analysis of both eyes’ field of view found that the eye movements exclude the possibility that rats fuse the visual information into a single image like humans do. Instead, the eyes move in such a way that enables the space above them to be permanently in view – presumably an adaptation to help them deal with the major threat from predatory birds that rodents face in their natural environment.

Like many mammals, rats have their eyes on the sides of their heads. This gives them a very wide visual field, useful for detection of predators. However, three-dimensional vision requires overlap of the visual fields of the two eyes. Thus, the visual system of these animals needs to meet two conflicting demands at the same time; on the one hand maximum surveillance and on the other hand detailed binocular vision.


The research team from the Max Planck Institute for Biological Cybernetics have now, for the first time, observed and characterised the eye movements of freely moving rats. They fitted minuscule cameras weighing only about one gram to the animals’ heads, which could record the lightning-fast eye movements with great precision. The scientists also used another new method to measure the position and direction of the head, enabling them to reconstruct the rats’ exact line of view at any given time.


The Max Planck scientists’ findings came as a complete surprise. Although rats process visual information from their eyes through very similar brain pathways to other mammals, their eyes evidently move in a totally different way. “Humans move their eyes in a very stereotypical way for both counteracting head movements and searching around. Both our eyes move together and always follow the same object. In rats, on the other hand, the eyes generally move in opposite directions,” explains Jason Kerr from the Max Planck Institute for Biological Cybernetics.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Brain overload as toddler explains missing childhood memories

Brain overload as toddler explains missing childhood memories | Amazing Science |

Scientists -- and parents -- have long wondered why we don’t remember anything that happened before age 3. As all parents know, no matter how momentous an event is in a toddler’s life, the memory soon drifts away and within months there isn’t even a wisp of it left.


Now a new study shows that “infantile amnesia” may be due to the rapid growth of nerve cells in the hippocampus, the brain region responsible for filing new experiences into long-term memory. The study was presented Friday at the annual meeting of the Canadian Association for Neuroscience.


While youngsters do seem to remember important events for a short time after they occur, they lose these memories as time goes by, says study co-author Paul Frankland, a senior scientist at the Hospital for Sick Children in Toronto. “They can’t form stable memories of what happens in the first few years,” Frankland says. “I have a daughter who is 4 years old and because we were working on this study, I would always ask her questions about her memories of places we visited 2, 3 months ago. It’s clear that she can form memories with quite some detail. But four years from now she won’t remember anything.”

Frankland suspected that memories actually got filed away into long-term storage, but that the hippocampus lost track of where they’d been stacked during the rapid growth phase that takes place in the first few years of life.

As the hippocampus matures, huge numbers of new neurons come on line and need to be hooked into existing circuits, he says. The most likely scenario is that in all that restructuring, the brain “forgets” where it stored the memories.


As the expansion slows down, the brain can better keep track of where everything is filed away – so long-term memory gets better as youngsters get older.


To test his theory, Frankland gathered up some baby mice and slowed down the rate at which new neurons were formed in the hippocampus.

Normally baby mice have the same problem with long-term memory that human toddlers do – if you teach them to navigate a maze, after a few days they’ll forget how to find their way around. But with neurons being produced more slowly, the mice now were able to form long-term memories and remember how to get through the maze.

Dr. Liana Apostolova of the UCLA Brain Research Institute was delighted to have an answer to why her 6-year-old doesn’t seem to remember things that she recollects as very important. "This is a very interesting finding,” she says. “And it ties in greatly with what's in the literature."

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Amazing Science: Paleontology Postings

Amazing Science: Paleontology Postings | Amazing Science |

Paleontology is the scientific study of prehistoric life and includes the study of fossils to determine organisms' evolution and interactions with each other and their environments. Paleontology lies on the border between biology and geology, and shares with archaeology a border that is difficult to define. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, about 3,800 million years ago.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Genetically modified purple tomato 'tastier than normal varieties'

Genetically modified purple tomato 'tastier than normal varieties' | Amazing Science |

A genetically modified purple tomato that is tastier than normal varieties and can last for more than a month before going off has been invented by scientists. The GM tomato, which gains its unusual color from a natural pigment known as anthocyanin, could be picked and shipped later due to its longer shelf life, allowing more time for flavour to develop on the vine.


Tests showed the shelf life of the tomatoes more than doubled from an average of 21 to 48 days after genetic modification, and they were less likely to go mouldy after harvest.


The strain has also been found in earlier studies to fight cancer in mice due to its high levels of antioxidants, and scientists say its qualities could be replicated in other soft fruits like strawberries and raspberries.


The tomatoes were modified by scientists at the John Innes Centre in Norfolk to contain two genes from the snapdragon which “switch on” a set of dormant genes in the tomato, causing them to produce more anthocyanin.


The pigment occurs naturally in various plants and flowers, and is responsible for many of the blues, reds and purples seen in nature, but also ramps up levels of antioxidants.


The goal of the project was to produce fruit with higher antioxidant levels which could benefit health, and earlier studies have shown that they helped extend the lives of cancer-prone mice by 30 per cent.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Scientists offer first definitive proof of bacteria-feeding behavior in green algae

Scientists offer first definitive proof of bacteria-feeding behavior in green algae | Amazing Science |

A team of researchers has captured images of green alga consuming bacteria, offering a glimpse at how early organisms dating back more than 1 billion years may have acquired free-living photosynthetic cells. This acquisition is thought to have been a critical first step in the evolution of photosynthetic algae and land plants, which, in turn, contributed to the increase in oxygen levels in Earth's atmosphere and ocean and provided one of the conditions necessary for animal evolution.

In a paper that appears in the June 17, 2013 issue of Current Biology and is available online today, researchers identify a mechanism by which a green alga that resembles early ancestors of the group engulfs bacteria, providing conclusive evidence for a process that had been proposed but not definitely shown.


"This behavior had previously been suggested but we had not had clear microscopic evidence until this study," said Eunsoo Kim, assistant curator in the Museum's Division of Invertebrate Zoology and corresponding author on the paper. "These results offer important clues to an evolutionary event that fundamentally changed the trajectory of the evolution of not just photosynthetic algae and land plants, but also animals."

In green algae and land plants, photosynthesis, or the conversion of light into food, is carried out by a specialized cell structure known as a chloroplast. The origin of chloroplast is linked to endosymbiosis, a process in which a single-celled eukaryote—an organism whose cells contain a nucleus—captures a free-living photosynthetic cyanobacterium but does not digest it, allowing the photosynthetic cell to eventually evolve into a chloroplast. The specific feeding mechanisms for this process, however, have remained largely unknown until now.

In this study, researchers used transmission electron microscopy and feeding and staining experiments to take conclusive images showing how a basic green alga from the genus Cymbomonas feeds on bacteria. The alga draws bacterial cells into a tubular duct through a mouth-like opening and then transports these food particles into a large, acidic vacuole where digestion takes place. The complexity of this feeding system in photosynthetic modern alga suggests that this bacteria-feeding behavior, and the unique feeding apparatus to support it, descend from colorless ancestors of green algae and land plants and may have played important roles in the evolution of early photosynthetic eukaryotes, the precursors to plants like trees and shrubs that cover the Earth today.

No comment yet.