Tag Archives: science explained

All present-day Life on Earth Has A Single Ancestor

All present-day life arose from a single ancestor

All life on Earth shares a single common ancestor, a new statistical analysis confirms.
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Because microorganisms of different species often swap genes, some scientists have proposed that multiple primordial life forms could have tossed their genetic material into life’s mix, creating a web, rather than a tree of life.
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A universal common ancestor is at least 10^2,860 times more probable than having multiple ancestors, Theobald calculates.
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For his analysis, Theobald selected 23 proteins that are found across the taxonomic spectrum but have structures that differ from one species to another. He looked at those proteins in 12 species – four each from the bacterial, archaeal and eukaryotic domains of life.

Then he performed computer simulations to evaluate how likely various evolutionary scenarios were to produce the observed array of proteins. Theobald found that scenarios featuring a universal common ancestor won hands down against even the best-performing multi-ancestor models.

Very interesting. Surprising too. As the article points out this doesn’t mean all life ever on Earth evolved from the single ancestor – life that has gone extinct could be from outside this single “tree.”

Mycoremediation and its Applications In Oil Spills

The webcast shows a talk by mycologist Paul Stamets on Bioremediation with Fungi (an Excerpt from Mushrooms as Planetary Healers). In response he to the British Petroleum/Halliburton oil spill he posted a message, Fungi Perfecti: the petroleum problem

Various enzymes (from mushroom mycoremediation) breakdown a wide assortment of hydrocarbon toxins.
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My work with Battelle Laboratories, in collaboration with their scientists, resulted in TAH’s (Total Aromatic Hydrocarbons) in diesel contaminated soil to be reduced from 10,000 ppm to < 200 ppm in 16 weeks from a 25% inoculation rate of oyster (Pleurotus ostreatus) mycelium, allowing the remediated soil to be approved for use as landscaping soil along highways. [paper]
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Aged mycelium from oyster mushrooms (Pleurotus ostreatus) mixed in with ‘compost’ made from woodchips and yard waste (50:50 by volume) resulted in far better degradation of hydrocarbons than oyster mushroom mycelium or compost alone.
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Oyster mushrooms producing on oil contaminated soil (1–2% = 10,000–20,000 ppm)… Soil toxicity reduced in 16 weeks to less than ~ 200 ppm, allowing for plants, worms and other species to inhabit whereas control piles remained toxic to plants and worms.
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New crop of mushrooms form several weeks later [after contaminating with oil]. The spores released by these mushrooms have the potential – as a epigenetic response – to pre-select new strains more adaptive to this oil-saturated substrate.
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I proposed in 1994 that we have Mycological Response Teams (MRTs) in place to react to catastrophic events, from hurricanes to oil spills. We need to preposition composting and mycoremediation centers adjacent to population centers
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On a grand scale, I envision that we, as a people, develop a common myco-ecology of consciousness and address these common goals through the use of mycelium. To do so means we need to spread awareness and information. Please spread the word of mycelium.

A Breakthrough Cure for Ebola

A breakthrough cure for Ebola By Steven Salzberg

Last week, in what may be the biggest medical breakthrough of its kind in years, a group of scientists published results in The Lancet describing a completely new type of anti-viral treatment that appears to cure Ebola. They report a 100% success rate, although admittedly the test group was very small, just 4 rhesus monkeys.

This is a breakthrough not only because it may give us a cure for an uncurable, incredibly nasty virus, but also because the same method might work for other viruses, and because we have woefully few effective antiviral treatments. We can treat bacterial infections with antibiotics, but for most viruses, we have either a vaccine or nothing. And a vaccine, wonderful as it is, doesn’t help you after you’re already infected.

The scientists, led by Thomas Geisbert at Boston University, used a relatively new genomics technique called RNA interference to defeat the virus. Here’s how it works.
First, a little background: the Ebola virus is made of RNA, just like the influenza virus. And just like influenza, Ebola has very few genes – only 8. One of its genes, called L protein, is responsible for copying the virus itself. Two others, called VP24 and VP35, interfere with the human immune response, making it difficult for our immune system to defeat the virus.

Geisbert and his colleagues (including scientists from Tekmira Pharmaceuticals and USAMRIID) designed and synthesized RNA sequences that would stick to these 3 genes like glue. How did they do that? We know the Ebola genome’s sequence – it was sequenced way back in 1993. And we know that RNA sticks to itself using the same rules that DNA uses. This knowledge allowed Geisbert and colleagues to design a total of 10 pieces of RNA (called “small interfering RNA” or siRNA) that they knew would stick to the 3 Ebola genes. They also took care to make sure that their sticky RNA would not stick to any human genes, which might be harmful. They packaged these RNAs for delivery by inserting them into nanoparticles that were only 81-85 nanometers across.
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Why Does the Moon Appear Larger on the Horizon?

Why does the Moon look so huge on the horizon?

If you’ve ever seen the Moon rising over the horizon, looking so fat and looming that you felt like you could fall right into it, then you’ve been a victim of the famous Moon Illusion. And it is an illusion, a pervasive and persuasive one.
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When the Moon is on the horizon, your brain thinks it’s far away, much farther than when it’s overhead. So the Ponzo Illusion kicks in: your brain sees the Moon as being huge, and it looks like you could fall into it. The Illusion works for the Sun, too. In fact, years ago I saw Orion rising over a parking lot, and it looked like it was spread across half the sky. It’s an incredibly powerful illusion.

Oddly enough, when it’s on the horizon, the Moon actually is farther away than when it’s overhead. Not by much, really, just a few thousand kilometers (compared to the Moon’s overall distance of about 400,000 kilometers).
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So the Moon Illusion is just that. It’s not the air acting like a lens, or foreground objects making it look big by comparison. It’s just the way we see the shape of the sky together with the well-known Ponzo Illusion.
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Science taking something we perceive as real, breaking it down, and showing it to be an interesting but decidedly unreal illusion? Well, that’s what science does! It helps us not only understand the world better, but it also makes the world cooler, too.

Why Planes Need to Avoid Fine Volcanic Ash

Volcanic ash: why it’s bad for planes

Aircraft avoid any airspace that has volcanic ash in it for a simple reason: the ash can wreck the function of propeller or jet aircraft, because it is so fine [less than 2mm in diameter, and some as fine as 6 microns] that it will invade the spaces between rotating machinery and jam it – the silica melts at about 1,100C and fuses on to the turbine blades and nozzle guide vanes (another part of the turbine assembly), which in modern aircraft operate at 1,400C.

That, in turn, can be catastrophic – as the crew of two aircraft, including a British Airways Boeing 747, discovered in 1982 when they flew through an ash cloud from the Galunggung volcano in Indonesia. On both planes, all four engines stopped; they dived from 36,000ft (11km) to 12,000ft before they could restart them and make emergency landings.
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The Icelandic plume has been thrown to between 6km and 11km into the atmosphere – exactly the height that aircraft would be flying.

Passengers on the BA flight that hit the cloud in 1982 said the engines looked unusually bright: soon after all four flamed out. “I don’t believe it – all four engines have failed!” said the flight engineer. The crew were prepared to ditch, and the captain told the passengers: “Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them under control. I trust you are not in too much distress.”

Luckily, three of the engines could be restarted. The plane landed safely, and nobody was injured.

Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

Climate scientists from all over the globe are now able to test their climate models under extreme conditions thanks to Professor Minik Rosing, University of Copenhagen. Rosing has solved one of the great mysteries and paradoxes of our geological past, namely, “Why the earth’s surface was not just one big lump of ice four billion years ago when the Sun’s radiation was much weaker than it is today.” Until now, scientists have presumed that the earth’s atmosphere back then consisted of 30% carbon dioxide (CO2) which ensconced the planet in a protective membrane, thereby trapping heat like a greenhouse.

The faint early sun paradox
In 1972, the late, world famous astronomer Carl Sagan and his colleague George Mullen formulated “The faint early sun paradox. ” The paradox consisted in that the earth’s climate has been fairly constant during almost four of the four and a half billion years that the planet has been in existence, and this despite the fact that radiation from the sun has increased by 25-30 percent.

The paradoxical question that arose for scientists in this connection was why the earth’s surface at its fragile beginning was not covered by ice, seeing that the sun’s rays were much fainter than they are today. Science found one probable answer in 1993, which was proffered by the American atmospheric scientist, Jim Kasting. He performed theoretical calculations that showed that 30% of the earth’s atmosphere four billion years ago consisted of CO2. This in turn entailed that the large amount of greenhouse gases layered themselves as a protective greenhouse around the planet, thereby preventing the oceans from freezing over.

Mystery solved
Now, however, Professor Minik Rosing, from the Natural History Museum of Denmark, and Christian Bjerrum, from the Department of Geography and Geology at University of Copenhagen, together with American colleagues from Stanford University in California have discovered the reason for “the missing ice age” back then, thereby solving the sun paradox, which has haunted scientific circles for more than forty years.

Professor Minik Rosing explains, “What prevented an ice age back then was not high CO2 concentration in the atmosphere, but the fact that the cloud layer was much thinner than it is today. In addition to this, the earth’s surface was covered by water. This meant that the sun’s rays could warm the oceans unobstructed, which in turn could layer the heat, thereby preventing the earth’s watery surface from freezing into ice. The reason for the lack of clouds back in earth’s childhood can be explained by the process by which clouds form. This process requires chemical substances that are produced by algae and plants, which did not exist at the time. These chemical processes would have been able to form a dense layer of clouds, which in turn would have reflected the sun’s rays, throwing them back into the cosmos and thereby preventing the warming of earth’s oceans. Scientists have formerly used the relationship between the radiation from the sun and earth’s surface temperature to calculate that earth ought to have been in a deep freeze during three billion of its four and a half billion years of existence. Sagan and Mullen brought attention to the paradox between these theoretical calculations and geological reality by the fact that the oceans had not frozen. This paradox of having a faint sun and ice-free oceans has now been solved.”

CO2 history iluminated
Minik Rosing and his team have by analyzing samples of 3.8-billion-year-old mountain rock from the world’s oldest bedrock, Isua, in western Greenland, solved the “paradox”.

But more importantly, the analyses also provided a finding for a highly important issue in today’s climate research – and climate debate, not least: whether the atmosphere’s CO2 concentration throughout earth’s history has fluctuated strongly or been fairly stable over the course of billions of years.

“The analyses of the CO2-content in the atmosphere, which can be deduced from the age-old Isua rock, show that the atmosphere at the time contained a maximum of one part per thousand of this greenhouse gas. This was three to four times more than the atmosphere’s CO2-content today. However, not anywhere in the range of the of the 30 percent share in early earth history, which has hitherto been the theoretical calculation. Hence we may conclude that the atmosphere’s CO2-content has not changed substantially through the billions of years of earth’s geological history. However, today the graph is turning upward. Not least due to the emissions from fossil fuels used by humans. Therefore it is vital to determine the geological and atmospheric premises for the prehistoric past in order to understand the present, not to mention the future, in what pertains to the design of climate models and calculations,” underscores Minik Rosing.

Full press release from the University of Copenhagen in Denmark.

Taste Cells in the Stomach and Intestine

Stomach’s Sweet Tooth

Taste, scientists are discovering, is a whole-body sensation. There are taste cells in the stomach, intestine and, evidence suggests, the pancreas, colon and esophagus. These sensory cells are part of an ancient battalion tasked with guiding food choices
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Newly discovered taste cells in the gut appear to send a “prepare for fuel” message to the body, a finding that may explain a link between diet soda and diabetes risk.
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The gut’s taste cells appear to be built from the same machinery as the taste cells of the tongue, the structures of which scientists have only recently nailed down. Taste cells interact with what are called “tastants” via receptors, specialized proteins that protrude from cell walls and bind to specific molecules drifting by. When a tastant binds to a receptor, it signals other molecules that, in the mouth, immediately send an “accept” or “reject” message to the brain.
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Gut taste cells appear to regulate, in part, secretion of insulin, a hormone crucial for telling body tissues whether they should tap newly arrived glucose or valuable stored fat for energy.

Antibiotics Breed Superbugs Faster Than Expected

We continue to endanger ourselves by using antibiotics inappropriately. This is one of many things that happen when the public at large is ignorant about science and ignores scientific evidence. I don’t believe people want to put other people’s lives in danger. But our behavior in the face of the evidence has us doing just that. I believe because we don’t value science rather than because we don’t care about putting others (and ourselves) in danger. Antibiotics Breed Superbugs Faster Than Expected

Bacteria don’t just develop resistance to one drug at a time, but to many — and at accelerated rates. That’s because antibiotics boost bacterial production of free-radical oxygen molecules that damage bacterial DNA. Repairs to the DNA cause widespread mutations, giving bacteria more chances to randomly acquire drug-resistant traits.
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Drug resistance is a serious public health concern. According to the federal Centers for Disease Control and Prevention, 70 percent of 1.7 million infections acquired in hospitals every year are resistant to at least one drug. Those infections annually kill 99,000 Americans — more than double the number that die in car crashes.

Drugs that once destroyed almost any bacteria now kill only a few, or don’t work at all. In the case of some drugs, like Cipro, the decline is dramatic: Where in 1999 it worked against 95 percent of E. coli, it treated only 60 percent by 2006. Against lung infection-causing Acinobacter, its effectiveness fell by 70 percent in just four years.

Though drug resistance is ultimately inevitable, conventional wisdom holds that antibiotics consumed at suboptimum doses hasten the process. Bugs that would have succumbed to a larger dose live to multiply, pushing the strain as a whole closer to resistance. That happens when a prescription goes unfinished, or when antibiotics used on farms enter food and water at low levels.
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Of the 35 million pounds of antibiotics consumed annually in the United States, 80 percent goes to farm animals. Much of it is used to treat diseases spread by industrial husbandry practices, or simply to accelerate growth. As a result, farms have become giant petri dishes for superbugs, especially multidrug-resistant Staphylococcus aureus, or MRSA, which kills 20,000 Americans every year – more than AIDS.

Alarming cases of farm-based MRSA and other diseases led to a proposed Congressional law restricting the use of agricultural antibiotics. That bill, supported by the American Medical Association and American Public Health Association, is opposed by farm lobbyists and remains stuck in committee.

Researchers Explain How Rotifers Thrive Despite Forgoing Sex

Bdelloid rotifers haven’t had sex for at least thirty million years. Most asexual animals are doomed to extinction. The excellent show, Science Friday, looks at the extraordinary adaptations that allow rotifers to thrive sex-free.

For millions of years, the rotifers have reproduced asexually, flying in the face of an idea known as the Red Queen Hypothesis, which states that without the advantage of sexual reproduction, more-rapidly evolving parasites and predators will eventually doom the asexual species. Now, the researchers studying the tiny organism say that its ability to dry up and blow away to greener pastures may have given the rotifers a hidden tactical edge in this evolutionary war.

The webcast provides a nice overview of the research. Every week Science Friday provides many such interesting reviews of recent scientific research.

What Are Rotifers?

Rotifers are small, mostly freshwater animals, and are amongst the smallest members of the Metazoa — that group of multicellular animals which includes humans, and whose bodies are organized into systems of organs.
Most rotifers are about 0.5mm in length or less, and their bodies have a total of around a thousand cells. This means that their organ systems are a greatly simplified distillation of the organ systems found in the bodies of the higher animals.

A typical rotifer might have a brain of perhaps fifteen cells with associated nerves and ganglia, a stomach of much the same number, an excretory system of only a dozen or so cells, and a similarly fundamental reproductive system. They have no circulatory system. It is an anomaly that despite their complexity, many rotifers are much smaller than common single-celled organisms whose world they share.
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they are able to survive long periods — even perhaps hundreds of years — in a dried or frozen state, and will resume normal behaviour when rehydrated or thawed.
Secondly, they exhibit what biologists call cell constancy — they grow in size not by cell division, but by increase in the size of the cells which they already have.

Slime Mold and Engineers Design Similar Solution

Slime Mold Grows Network Just Like Tokyo Rail System

Talented and dedicated engineers spent countless hours designing Japan’s rail system to be one of the world’s most efficient. Could have just asked a slime mold.

When presented with oat flakes arranged in the pattern of Japanese cities around Tokyo, brainless, single-celled slime molds construct networks of nutrient-channeling tubes that are strikingly similar to the layout of the Japanese rail system, researchers from Japan and England report Jan. 22 in Science. A new model based on the simple rules of the slime mold’s behavior may lead to the design of more efficient, adaptable networks, the team contends.
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The yellow slime mold Physarum polycephalum grows as a single cell that is big enough to be seen with the naked eye. When it encounters numerous food sources separated in space, the slime mold cell surrounds the food and creates tunnels to distribute the nutrients. In the experiment, researchers led by Toshiyuki Nakagaki, of Hokkaido University in Sapporo, Japan, placed oat flakes (a slime mold delicacy) in a pattern that mimicked the way cities are scattered around Tokyo, then set the slime mold loose.
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Initially, the slime mold dispersed evenly around the oat flakes, exploring its new territory. But within hours, the slime mold began to refine its pattern, strengthening the tunnels between oat flakes while the other links gradually disappeared. After about a day, the slime mold had constructed a network of interconnected nutrient-ferrying tubes. Its design looked almost identical to that of the rail system surrounding Tokyo, with a larger number of strong, resilient tunnels connecting centrally located oats. “There is a remarkable degree of overlap between the two systems,” Fricker says.