Researchers have been able to disable bacteria that cause ulcers by removing the bacteria’s ability to get close to the stomach wall.

This new knowledge about how the immune system responds toH. pylori infections could be used to screen for patients more susceptible to stomach ulcers and cancer, and perhaps to create more targeted therapies for those already affected.

In order to both survive and cause inflammation in the stomach, bacteria need to get to the side of the stomach “and set up shop there, living adjacent to your stomach cells, in a little kind of cozy home,” says Karen Ottemann, whose study was published this week in the early online edition of the Proceedings of the National Academy of Sciences. Unlike the acidic middle of the stomach, “the pH is closer to neutral and there’s food coming out of the cells,” she notes.

Ottemann found that the bacteria’s ability to move away from an acidic environment and towards one with food, called chemotaxis, was crucial to causing inflammation in the stomach. “To live really cozy like that,” she explains, “they need to be able to swim, and they need to be able to know where they’re going to direct their swimming.”

By swimming close to host cells, the bacteria are normally able to send out proteins that cause the cells of the stomach wall to burst. This cell death, combined with the presence of the bacteria in the stomach, puts the body’s immune system on high alert.

But removing the gene that allows bacteria to do chemotaxis prevented them from being able to hover near their host cells in mouse stomachs. Instead, the bacteria swam aimlessly, unable to aim their destructive proteins at host cells.

The mere presence of H. pylori in the stomach is not enough to start a severe immune response, since the body could just be responding to dead floating bacteria. Without the second crucial component—cell death—the immune system will not trigger damaging inflammation. “Many bacteria have this ability to do chemotaxis,” says Ottemann, “but they had not been studied in very much detail in terms of how the ability to do chemotaxis was used inside of infected animals or humans.”

More than half of people are infected with H. pylori, but over eighty percent of those infected never experience any negative symptoms. Patients who do have symptoms may be the victims of a “frustrated immune system” struggling to rid itself of H. pyloriwhile causing more damage to the body’s own cells than to the bacteria, according to immunologist Martha Zuniga at theUniversity of California, Santa Cruz.

Vicki Auerbach Stone, who studies the immune system, says the research paints a fuller picture of all the necessary conditions for H. pylori to have its effect. While scientists mostly study the molecules that are the immediate cause of inflammation, there are other factors that have to be in place in order for the molecule to accomplish its goal. “And chemotaxis is an example of something like that,” she says. “It’s getting the bacteria to the right place to have an effect.”

Since only a small number of people with H. pylori infections have severe reactions, while most cases go unnoticed, researchers hope that this new knowledge about the specific kind of immune response H. pylori can generate will help them to single out people who are more likely to experience symptoms of infection.

Zuniga is interested in these different immune response profiles, asking, “What distinguishes people that can have an H. pylori infection and not even know it for their entire lives from the people who develop pathology—who get ulcers, or ultimately cancer?”

“My own personal prediction would be that it’s the severity of the immune response,” she explains, “and that genetic differences among different people would predispose you to give a very strong anti-inflammatory response that isn’t very effective at clearing bacteria, but that does cause pathology.”

Part of H. pylori’s effectiveness is in its ability to manipulate the immune system. The first stage of the immune response, called the innate response, detects both the presence of the bacteria in the stomach and the death of stomach wall cells. These two events combined set off a cascade of events resulting in the second adaptive response, which recruits cells that can target the infection more specifically.

But H. pylori is able to trick the innate immune system into setting off the wrong kind of adaptive response: one that does not target the bacteria very effectively, but that does cause intense inflammation. People who experience symptoms of a H. pyloriinfection have adaptive immune responses that send out more highly inflammatory immune cells, which cause rampant damage along the lining of the stomach. The bacteria thrive in inflamed areas, and the immune response ends up targeting the body’s cells rather than getting rid of the bacteria. This results in chronic inflammation.

But without chemotaxis, the bacteria were unable to trick the innate immune system. Even though the genetically altered bacteria continued to survive in the mouse’s stomachs, they did not cause damage. With this new knowledge about the behavior of ulcer-causing bacteria, researchers can begin to imagine how it might be applied to preventing ulcers and stomach cancer.

In addition to identifying people whose immune systems are more likely to have dramatic responses, bacteriologists like Daniel Kadouri, who works on developing therapies that use bacteria, speculate it might be possible to use probiotics to make the stomach a less hospitable environment for H. pylori by interfering with its ability to do chemotaxis.

Matt Traxler, a microbiologist at the Harvard Medical School, points out that developing therapies that target chemotaxis in H. pylori could also have more widespread applications. Chemotaxis is a common ability among bacteria, since most bacteria use whip-like tails called flagella to move around, and chemotaxis helps determine in which direction the bacteria should move.

If scientists devise a way to prevent H. pylori from doing chemotaxis in the stomach, Traxler imagines, they might be able to apply that knowledge to many other pathogens that also use chemotaxis to damage their hosts.

As evidence grows that having H. pylori in the stomach may lead to some health benefits, such as the prevention of esophageal cancer and asthma, these modified, less harmful bacteria are of interest to immunologists. However, Ottemann and others concede that using these modified bacteria purely as a treatment tool is a distant prospect that requires much more research into both effectiveness and safety.

“I think there’s a lot of interest in the idea that you might want to control your microbial flora so as to either promote a health state or to demote a disease state,” says Ottemann. But for the moment with H. pylori, “I just think we’re a little ways off from that.”

In September 1943, a flurry of activity surrounded MIT’s biological engineering research labs. In the midst of battle in North Africa, twenty German prisoners had been taken by American forces. They were first shipped to a holding facility in Cameron, Virginia, and then to researchers in building 35 at MIT. Starting up spectrometers and microscopes, the scientists eagerly examined their captives: twenty samples of German rations—ingredients, main courses, and desserts—begging for a thorough analysis.

Just down the street from physics labs creating battle-winning radar technology and chemistry labs churning out isotopes for atomic bombs, a quieter wartime project was underway. From July 1942 to October 1945, the Office of the Quartermaster General in the U.S. War Department commissioned scientists at MIT to research and design rations for soldiers in the Second World War.

Many of the project titles from those three years, now stored in the MIT archives, conjure up stark images of the life of a World War II soldier. Researchers abandoned their teaching careers to throw themselves into inventing an all-purpose emergency food capable of sustaining an isolated individual for an indefinite period of time, a more condensed soda cracker, and a concentrated food product for mountain troops.

But perhaps surprisingly, this ultra-practical research made up only a small portion of their work. Early on, scientists came up with a new way to flash freeze entire meals, which allowed the diet of the American soldier overseas to not differ much from what his wife or mother would have served him: beef steak, beef stew, meat loaf, roast beef hash, creamed chicken, and apple brown betty. The easy familiarity of the recipes for these dishes, which read like just about any cookbook from the 1940s, is only disrupted in the final step of each recipe, which calls for running the finished meal through an industrial-strength freezer.

Familiar as they were, most of the foods the researchers sent overseas were driven by practicality. Scientists strove to maximize calories per gram of highly stable nourishment—the only real, tangible measure of their success. Their discussion of food is so overwhelmingly technical it is sometimes easy to forget that the outcomes of their experiments were meant to be eaten.

But among the more typical foods was something less expected. In 1944, the scientists decided to tackle canning apple pie—and not just any apple pie, but one that would give the real thing a run for its money.

Soggy crust was not an option. The researchers struggled to make a crust whose quality was not compromised by the harsh conditions required to preserve it. They attempted several crust arrangements within the can: first with crust only on the top and bottom, and then another version also lining the sides. They experimented with different lengths of time between the baking of the pie in the can and the processing period, to see if letting the crust set before preserving would help maintain the flakiness.

Underneath the researchers’ highly technical language and the discussions of albumin pH and molecular composition of crust, there is an unmistakable soft touch. They wanted to give soldiers something that reminded them of home, something their mothers would have fed them if they could. They spent months and sometimes years tinkering and experimenting and reevaluating in order to give a young man—cold, scared, and far from home—not just what his body needed, but what his homesick spirit craved. Soda crackers and scrapple, the staples of subsistence, were not good enough. But crisp, flaky-crusted canned apple pie: Now that was a wartime assignment worthy of pursuit.

Some bat species can dramatically change the size and shape of their ears faster than humans can blink an eye, researchers have shown.

Scientists already knew that bats could change the direction of their ears depending on where a sound was coming from, like shining a flashlight around a room. New data now show that bats can also reshape their outer ears, stretching their ears to pick up sound from a wide field and then focusing back to tiny targets very quickly.

Rapidly switching back and forth from one ear shape to another can help the bat simultaneously learn about its environment and chase down an insect for dinner. Rolf Mueller, a researcher atVirginia Tech whose study was recently published in Physical Review Letters, hopes that the finding can be used to create more sophisticated sonar technology.

Working closely with bats after receiving funding to build a robotic one, Mueller soon realized how little was known about the mechanics of bat ears. “Bats are pure physicists,” says Mueller. He wants to build sonar technology that is not merely loosely inspired by bats but that pays deep attention to how bats expertly collect sound.

Bats perform several crucial tasks during echolocation. In order to avoid obstacles, they first need to acoustically scan their environment to learn the location of both objects (such as trees) and targets (like insects). For these tasks, bats cast a wide net of echoes and also make their ears larger to hear more of the echoes coming back. Once they have a sense of their whereabouts, the bats then aim to identify what each of those objects are, which requires sending and receiving very focused echoes.

“Sensitivity is just like money,” according to Mueller. “You can spend it only once. So if you know the [target] direction, you put it all there. If you don’t, you spread it out.”

But since the bat cannot both cast a wide net and do focused identification at the same time, they have to do one right after the other. And because bats echolocate in the midst of flying and hunting, the change between one function and the other needs to happen as quickly as possible. The bats can change from one ear shape to another in about 100 milliseconds: half the time it takes a human to blink an eye.

Rigid movements of the bats’ entire ear—the flashlight-style sweeps—have been documented by scientists for years, but Mueller’s is the first work to quantify not just the change in direction of the ear but also its change in shape. Mueller is now working with a few graduate students to improve sonar technology by mimicking the bat behaviors he observed. They are experimenting with making sonar dishes in softer materials that can respond and change the same way bat ears do.

Ellen Covey, a neurobiologist who studies bat hearing at the University of Washington, describes the bats’ ear movements as a shift from “echolocation tunnel-vision” to a wider, more lateral field where the bats can capture varied echoes. “It’s a way of changing focus,” she says.

But she also points out that there is a great deal more happening during bat echolocation than just adjustments to ear shape. Bats have to parse out many different kinds of echoes coming from different places that hit their ears at the same time. Since bats usually fly in “cluttered spaces” filled with trees and leaves, they receive a near constant stream of environmental echoes they need to wade through in order to find moving insects. Additionally, bats need to contend with the fact that the echoes they send out interfere with the sound waves of the echoes coming back towards them.

Covey has found that bats actually process echolocation sounds in ways very similar to how human brains process language.

For now, Mueller and his team are focusing on making sonar dishes that mimic the ear movements of the bats. In addition to the size changes, they observed that the bats’ ears are in constant motion during the entire length of the echo—something our microphones and satellites do not yet do.

Scientists have cracked the genetic code of a “vampire bacterium” that survives by sucking the nutrients out of other living bacteria. This new information could someday be harnessed to fight infections in combination with traditional antibiotic therapies.

Micavibrio aeruginosavorus belongs to a small class of predatory bacteria that get their nutrients from other living bacteria rather than from the environment. This particular bacterium attaches to the outside of a host cell, penetrates its outer membranes, and extracts the nutrients it needs to survive, earning it its ghoulish title.

The vampire bacterium’s genes, recently sequenced and published in BioMed Central Genomics, show that it lacks an enzyme required to transport some amino acids from the environment into its cell. This means it has to seek out these nutrients from other bacteria instead. Because predator bacteria kill their prey in the process of extracting nutrients, researchers hope that predators could someday be used to help fight bacterial infections by eating and destroying pathogens.

Public recognition of bacteria’s benefits has grown in recent years, along with sales of probiotic yogurts and supplements. “We need to work with nature,” according to Daniel Kadouri, who contributed the microbiology research to the study. For years, he says, scientists attempted to hijack nature with harsh antibiotics which become obsolete after only a few years of use. Bacteria may prove to be a valuable weapon in controlling increasingly antibiotic-resistant infections. Among the vampire bacterium’s natural prey are Pseudomonas aeruginosa: the bacteria that cause lung infection in cystic fibrosis patients.

Scientists have known about predatory bacteria for years, but they are difficult to study because culturing them requires growing them along with their prey. This makes the predator bacteria difficult to isolate from their food later on. In cases like these, studying the genes is one of the most straightforward ways to learn about a bacterium’s biology.

Predator bacteria have several qualities that make them promising as treatment tools. First, they are very specific about the kinds of prey they target, so unlike many antibiotics, they can be used to treat infections without causing more widespread damage.

Predator bacteria are also skilled at cutting through biofilms: groups of bacteria that adhere with a dense slime, greatly increasing their antibiotic resistance. While drugs are relatively ineffective at penetrating biofilms, predator bacteria actually seem to prefer eating through biofilms since they are a concentrated source of prey.

Kadouri acknowledges the public squeamishness about using bacteria—presumably the enemy—as a medical treatment. He says that bacteria therapies are just one tool in the arsenal of fighting bacterial infection. “The idea is to keep your infection at bay so you can come in later with antibiotics in a low dose. Or your immune system can have a fighting chance.” Ultimately, he says, fighting infections with bacteria is no more frightening than blasting our systems with potent drugs.

Predator bacteria are most likely to be effective in localized infections, so Kadouri imagines they could be used to treat topical infections in wounds, such as those caused by shrapnel. Since the predator bacteria are much more specialized than any antibiotic we know of, they could treat the infection without also destroying the “good” bacteria that populate our bodies.

Kadouri and others recognize that more research is needed to ensure the predator bacteria targets are as specific as they seem to be. But Kadouri is optimistic that predator bacteria, combined with traditional antibiotics, could yield safer and more effective treatments than those currently available.

Matt Traxler, a microbiologist at the Harvard Medical School, shares that optimism. He points to the increasing public acceptance of bacteria—especially probiotics—as a force for health. “There’s definitely a hurdle in the public mind that needs to be crossed. But I think we’re approaching that every day.”

Vampire bacteria are just one species of predator bacteria. Others, like Bdellovibrio, which Kadouri’s lab is also studying for its therapeutic potential, target prey by entering their cell walls and eating them from the inside out. Bdellovibrio also has a different prey population than the vampire bacteria, widening the number of infections that could potentially be treated with bacteria-based therapies.

There are, indeed, moments in time when the heavens touch the earth, and the results are truly awesome: Natural glass, formed when sandy soil is melted by lightning and then quickly cooled, is wild in texture, color and shape, an eerie reflection of the stormy sky in which it was born.

Of course, there are simpler ways to make glass than to wait for perfect cosmic conditions. For thousands of years, humans have been making glass, which can be blown and molded to create myriad shapes. The MIT Glass Lab is responsible for an impressive number of these fantastical glass creations that push the limits of what we can create in this temperamental and delicate medium. At the MIT 150 exhibit at the MIT Museum, there are examples of glass formed into everything from pumpkins to abstract vases to musical instruments.

Though each of these sculptures has its own virtues, the glass oboe in particular highlights part of what makes glass so special. Even in its hardened state, glass lacks the crystallized structure of a solid material. It continues to flow like a liquid. Both dense and flexible, glass vibrates more easily than such materials as wood and metal. An oboe re-imagined in glass creates beautiful sounds that are almost impossibly clear in tone. But the resonant power of glass is perhaps nowhere better represented than in what Ben Franklin once called his most satisfying invention: the glass armonica.

Invented in 1761, the glass armonica consists of stacked and tuned globes of glass on a spindle. A musician pumps with her foot to make the glass spin and touches wet fingers to the glass to produce notes. The instrument operates on the same principles that make crystal wine glasses sing. A wet finger sliding along the rim of a glass—or a globe on the armonica—creates just enough friction to vibrate the glass. The vibrations are then transmitted to the air, where they create sound. Variations in the size of the glass or the amount of water inside change the frequency in the vibration, producing different notes.

Mozart was so deeply captivated by Franklin’s glass armonica that he composed two pieces specifically for it. Even the briefest listen to an adagio performed on glass is enough to understand why. The sound is spine-tingling. A perfect reflection of its origins, glass music is hauntingly ethereal, angelic, and unnerving—so artfully suspended in the air that it feels as though it is coming from everywhere and nowhere at once.

Since metals like gold and platinum should have been pulled into the earth’s iron core as it cooled over four billion years ago, their presence on the surface is a mystery. Scientists have wondered for decades if an ancient meteor shower was responsible, but testing this theory seemed impossible.

That is, until now. To sleuth out whether gold once rained down from the heavens, scientists recently turned to a less glamorous metal: tungsten. That’s because metals tend to travel in groups. The same meteors that may have delivered gold to earth would also have delivered tungsten. Though less glamorous than gold, tungsten is valuable as a clue. Depending on whether it originated on earth or in a meteor, tungsten has a slightly different mass—a trait that reveals its source.

Panning for miniscule quantities of tungsten in ancient rocks, though, is an enormous challenge. To carry out this detective work, Matthias Willbold at the University of Bristol in England exercised the most virtuous of scientific traits: patience. He ground up ancient rocks and painstakingly sorted the components. And he didn’t just sort twenty times more samples than previous researchers had tackled; he also ran his experiment five separate times. The process took over two years. “It comes down to detective work, like a CSI thing,” he says. “You get carried away.”

The result of Willbold’s investigation is the first evidence that ancient and modern rocks have different ratios of tungsten masses, suggesting that the precious metals we find in the earth’s oldest crust had a meteoric origin. Science—and the heavens—reward patience indeed.

In a surprising finding, researchers have found that the Milky Way may have gotten its spiral arms in a collision with a much smaller galaxy.

The team from the University of California, Irvine, and theUniversity of Pittsburgh spent a year creating a supercomputer model to simulate the dwarf galaxy Sagittarius colliding with the Milky Way, but unlike previous models, they included the dark matter that would have surrounded the smaller galaxy.

“In the past, people have always thought of the Milky Way as the big bad guy—it’s so massive it’s going to tear this little galaxy apart,” says UC/Irvine astrophysicist James Bullock, whose group published the results of their simulation this month in Nature. “But people hadn’t thought about it from the other direction.”

Scientists have long known that galaxy collisions take place all over the universe but have largely dismissed the importance the smaller galaxy has in shaping the larger one, since the small galaxy is usually destroyed during the collision. The Milky Way is over ten times as many light-years across as the Sagittarius dwarf galaxy and contains billions more stars.

“In the past,” according to Bullock, “when people thought about the Sagittarius interaction, people thought it was way too minor. Sagittarius was way too small to make anything interesting happen.”

The reason Sagittarius was underestimated in the past was because previous models did not include the dark matter that likely surrounded the galaxy before it collided with the Milky Way. Dark matter is invisible, but exerts the same gravitational power as visible matter.

Smaller galaxies like Sagittarius could be surrounded by a hundred times as much dark matter as visible matter. Bullock and his team studied isolated galaxies of similar size to Sagittarius to estimate how much dark matter surrounded the galaxy pre-collision.

Bullock’s simulation was run on a cluster of 48 computer processors for around five days at a time—totaling over 10,000 hours of computing time, which would take over a year on a single computer. The simulation produced coordinates for 30 million particles at various points in time, which was then visualized as a film.

Including the dark matter turned out to be crucial to the effect Sagittarius had on the Milky Way in the simulation. After setting initial conditions and letting the model run, Bullock’s group found that the simulation produced a galaxy that looked eerily similar to how the Milky Way appears today.

For Bullock, “it was a little bit of a surprise” that the simulation produced a model that so closely resembled our home galaxy. With the dwarf galaxy’s dark matter, it appeared that the Sagittarius collision could be largely responsible for the overall current structure of the Milky Way.

But Bullock is not ready to say that the Sagittarius collision was single-handedly responsible for the spiral arms of the Milky Way. He says it is more likely that it was one of several factors, including other collisions and the gravitational pull of stars and clusters already in the Milky Way.

Sergey Mashchenko, a cosmologist at McMaster University in Ontario, Canada, agrees that though the model is impressively detailed, it only considers one factor—the Sagittarius galaxy—when there could be an interaction of many factors. “There is no definite answer that spiral arms form only this way or that way,” he explains. “In reality, I think it is a mixture of all kinds of things. Maybe there is no single answer.”

“But as this paper suggests,” Mashchenko continues, “it might very well have been either this specific satellite, or maybe another one, or maybe a combination over the past several billion years which turned our galaxy into a spiral galaxy.”

About 80 to 90 percent of the dark matter in Sagittarius was ripped off in the first of its two collisions with the Milky Way, so the second collision had a much smaller impact. These two collisions occurred in the past two billion years. With so little dark matter remaining, Sagittarius’ third collision with the Milky Way, estimated to take place about 10 million years from now, will essentially be a non-event.

Imagine yourself standing on the shore of a river in eastern Australia, arms outstretched to avoid being nipped by the flailing, angry platypus you have suspended upside down by its tail. The scene is strange enough without considering the oddities of the animal you have captured: It has the fur of a mammal, the bill of a duck, and the tail of a beaver, and it lays eggs like a reptile. And it’s venomous. The platypus is one of a very select group of mammals that produces venom, and it is giving scientists clues into how and why venom evolved across species.

Right now, not much is known about the contents of platypus venom. Part of the reason for this is that platypuses are somewhat tough to come by. They don’t breed well in captivity, and concerns about disturbing them during mating season make them difficult to track down in the wild. Fortunately for us, field scientists like Tom Grant of the University of New South Wales regularly put themselves in the aforementioned strange scenarios on eastern Australian rivers. Grant and his colleagues lay nets in the water in hopes of trapping an animal, and when they have one, they grab it by its long tail and hold it upside down. Platypus venom spurs are located on the hind legs, so while one scientist holds the angry, dangling platypus by the tail as far away from himself as possible to avoid being stung, another holds a small pipette up to the spurs in hopes of extracting a little venom that can be stored and studied. The venom is strong enough to kill a dog and cause debilitating pain to a human. Just another day at the office.

The scientists’ troubles don’t end there. Only the male platypus produces venom, and only during mating season. (Scientists are not yet sure why, but most believe it’s because the venom is used for territorial defense while mating.) Unfortunately, this narrows both the window of time and number of subjects the scientists can study. And unlike more widely studied animals like spiders and snakes, platypuses can’t be electrically stimulated to release venom, so researchers have to rely on the trace amounts secreted through the spurs of captured platypuses. Reliably separating all the components of the venom takes a sample much larger than the mere 100 microliters field researchers are usually able to get.

Still, researchers have been able to investigate some fascinating questions about how venom evolved in animals like the platypus. Camilla Whittington at the University of Sydney is curious about why platypus venom has such a strikingly similar toxin profile to reptile venom, despite the fact that it evolved independently. She thinks the toxins in platypuses originally arose when a gene that coded for part of the immune system was accidentally duplicated. Accidental copies like this are often important tools in evolution, since the first intact version of the gene can perform its normal function while the second can try out new combinations without threatening the survival of the animal. In this case, the gene seems to have been one involved in breaking open the cell walls of invasive microbes that could have made the platypus sick. With a little evolutionary tinkering, the gene morphed into one that could break open the cells of predators and cause extreme pain and sometimes death.

Whittington says this kind of evolutionary development of venom from the immune system is fairly common, and is part of why we see the same kinds of venom cropping up in many different animals. She describes this phenomenon as a “venom motif” that nature selects for again and again. The reason? It works. Nature seems to have found a useful template for venom, and as long as it remains effective, anything that evolves to be venomous will very likely follow a venom motif, whether it’s mammalian, reptile, amphibian, or anything else.

There is still a great deal of work to be done on platypus venom, both on what’s in it and how it’s used. Who knows what other evolutionary secrets this anomalous Australian mammal will help uncover?

Photo Courtesy Stefan Kraft

PBS.org — Inside NOVA

The venom-spitting dinosaur in Jurassic Park may have been fictional, but in a great case of life imitating art, scientists have discovered evidence of a real venomous dinosaur that walked the earth in China over 120 million years ago. Sinornithosaurus is the first confirmed venomous dinosaur, but there is evidence that venom is even older than this most recent discovery–that creatures from up to 500 million years ago could also have been venomous. These ancient venomous creatures are giving us reason to believe that, evolutionarily speaking, not being venomous may actually be more noteworthy than being venomous.

David Burnham, a paleontologist at the Kansas University Natural History Museum, was hunting for raptor fossils in rural China when he and his colleagues stumbled across a new fossil skeleton with grooved teeth and an inexplicable gap in its skull. They puzzled over what these two clues could mean. And then one day, while examining the skulls of venomous komodo dragons, it suddenly clicked. The cavities in the raptor skull very closely resembled areas in the komodo dragon skull reserved for their venom glands. Burnham began to wonder, was it possible that this ancient raptor was also venomous?

Further investigation revealed that everything Sinornithosaurus (the newly named raptor species) would need to be venomous was there. The spaces in the skull would have made room for prominent venom glands, along with a drainage canal leading into the mouth and muscles to help pump out the venom. But this dinosaur’s venom-delivery mechanism was rather primitive. Unlike many modern snakes with long fangs in the front of their mouths that can forcefully eject venom at their prey (remember spitting cobras?),Sinornithosaurus had teeth with grooves for delivering venom that sat at the back of its mouth. Burnham suspects that over evolutionary time, tooth material closed in around the groove and migrated towards the front of the mouth, leading to something more closely resembling a cobra’s fangs. The grooved teeth mean that unlike its fictional Jurassic Park counterpart,Sinornithosaurus had to chew the venom into its prey, probably using it more as a stunning tool than a killing one. A handful of modern snakes, unsurprisingly called “rear-fanged snakes,” have retained theSinornithosaurus-style grooved teeth.

Discoveries like Sinornithosaurus give scientists more decisive clues into the evolutionary history of venom. But we have reason to believe that venom is much older than even the dinosaurs. The conodont, an eel-like creature that lived almost 500 million years ago, had the same kinds of grooved teeth found in Sinornithosaurus and other primitive venomous creatures. And the evolutionary influence of the conodont is far from slight: it gave rise to all fish and most vertebrates.

Most of us tend to think of venom as something unique that only belongs to a small subset of animals. We’ve certainly never seen a venomous sparrow, so we imagine that venom evolved recently enough to be confined to creatures like reptiles and spiders. The venomous conodont is changing the way we think about the uniqueness of venom among animals. Rather than spontaneously appearing in more modern reptiles, it seems that venom was there all along–and was just lost along several paths of the evolutionary tree, including our own.

Burnham sees this idea as a game-changer. He points to our recent revelation that there are far more venomous creatures out there than we previously thought. Just a few years ago there were only 200 species of fish described as venomous. Now there are over 1,200 and counting. Fossils of animals like the conodont and Sinornithosaurus help confirm the growing notion that venom is actually the rule rather than the exception, especially when it comes to more ancient creatures. Instead of asking why a particular species is venomous, Burnham now thinks, “The real question is, why isn’t something venomous?”

Image Courtesy David Burnham

PBS.org — Inside NOVA

There are more than 41,000 described species of spider, and over 99% of them are venomous. Mercifully, there are only four small groups of spiders whose venom is lethal to humans, but insects beware: Spider venom can inflict a cocktail of unpleasant symptoms, from full-body convulsions and paralysis to spontaneous cell death that dissolves your body while you’re still conscious. With so many species and so much time to diversify, spiders have developed methods to capture and kill just about every kind of insect prey out there. And now, humans are developing ways to take advantage of diverse spider toxins to create pesticides that kill insects without harming humans or the environment.

Greta Binford spends most of her time doing research at Lewis and Clark College in Oregon, but when she’s not in the lab, she can be found hunting down the deadly brown recluse spider everywhere from peculiar haunts like the basement of a Goodwill store in Los Angeles to the mountains in their native Peru. They are generalists that will eat pretty much anything that walks by, but other spiders are much more specialized. Tarantulas live in holes and only capture things that come near their dwellings; orb weavers catch insects in flight. A few species spit toxic glue at their prey; others dash underwater and bite fish. Most interesting of all to researchers like Binford is that all these spiders’ venoms reflect the diversity in how and what they catch.

Studying spider venom is an arduous task. There are two basic strategies: either examine the genes a spider expresses in the venom gland, or try and break down the venom itself. In the first case, Binford electrically stimulates a spider, waits 24 hours, and then pulls out the tiny fragments of genetic material floating around in the venom gland tissue. She can then use the fragments to piece together the whole genetic code for the venom. The second approach involves slowly and meticulously separating the components in a sample of venom and identifying each ingredient by matching its molecular weight against a database of known spider toxins. Though it sounds easier, this method has its own problems. There is no good database already in existence, and with as many as 4,000 components in a single spider’s venom, it can take a large sample and huge amount of time to parse them all out.

Binford uses the data she collects from venom to piece together the evolutionary history of spider species. But why bother? Binford explains that the most powerful tool we have in understanding venom is the evolutionary tree itself. There are over 41,000 spiders species alone, and perhaps hundreds of thousands of other venomous animals, so our current picture of how all the venomous species are related is fairly spotty. But a more complete understanding of how and where venom evolved would help explain how certain toxins ended up in certain places along the evolutionary tree. This could enable scientists to more easily decipher what’s in the venom samples they already have, and to make predictions about what kinds of toxins we’ll find in newly discovered species. Evolution turns out to be a great structural framework for understanding venom chemistry.

And understanding venom chemistry is beginning to have some exciting new applications. Glenn King, a professor at the University of Queensland in Australia, is developing ways to use components of spider venom as targeted pesticides. From an evolutionary perspective, this makes perfect sense. Spider venom has evolved specifically to target insects, so if we can isolate the toxic proteins that kill insects without harming humans, we’d have some very effective and completely biodegradable pesticides.

To figure out which proteins accomplish that goal, King tests possible toxins on newborn mice, mammals that are especially sensitive to neurotoxins. None of the toxins being developed are at all harmful to the newborn mice, even at very high doses. King acknowledges that a lot of people might be hesitant to spray their plants with spider toxins, but says this is a problem of perception rather than reality. Only a microscopic percentage of spider toxins are harmful to humans anyway, and tests like the ones on baby mice weed those out long before they come in contact with our food.

Evolution and natural selection may have created chemicals that do their jobs better than the synthetic ones humans create. We have nature–and the spiders themselves, of course–to thank for these incredible toxins. And as scientists continue fill in the gaps in the spider’s evolutionary tree, they are bound to discover even more ways to take advantage of their unique adaptations.

Image Courtesy Bruno Santos