A caecilian from the newly discovered family, coiled over her eggs.
After thousands of hours of digging in the north Indian jungle, scientists have discovered a new family of amphibians. But they don’t look much like frogs: they resemble nothing so much as big, fat nightcrawlers.
There are about 180 species worldwide of legless amphibians, called caecilians (pronounced just like “Sicilian”), which can grow to be up to three feet long and live only in wet, tropical regions. This newly defined Indian family, which falls within that group, includes several species new to science. Caecilians have unusual nesting habits: the females lay eggs deep in the soil and stay coiled around them, apparently without eating, for the 2-3 months it takes for them to hatch. One of the most striking videos we have of the new creatures is of young almost ready to be born squirming and writhing within the clear globes of their eggs, like eyeballs filled with living jelly (watch below).
Nematode worms live longer if their grandparents had particular genes.
But they don’t need to receive the genes themselves to feel the effects.
What’s the News: Scientists have discovered that worms who’ve been given mutated genes that let them live longer pass on their longevity to their descendants—even when the descendants don’t receive the genes. How does it work?
Taking advantage of the emerging technique of optogenetics, Harvard researchers report in the journal Nature Methods that they can target any individual neuron of the tiny transparent worm C. elegans, whether the creature is moving or at rest, and zap it with a laser to see what the particular cell does—move the worm to the left or right, or even cause it to lay eggs.
The whole process, from finding the cell to light hitting its target, takes about 20 milliseconds. As the worm’s position changes, that information is fed back into the computer program, and the laser is adjusted. If the worm crawls too far, a motorized microscope stage brings the animal back. One of the biggest benefits of the new method, [biologist William] Ryu says, is that it works in a roving animal. “The worms are not held down in any way — they’re freely moving. There aren’t many systems where you can look at such truly free organisms.” [Science News]
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Molecular biologist Mark Roth has found a way to bring frozen worm embryos and yeast cells back from the dead: he makes them hold their breath. In a paper to appear in the July 1 issue of Molecular Biology of the Cell, Roth questions the relationship between low oxygen, low temperatures, and life after death.
Freezing almost any living thing means certain doom, but, on occasion, organisms inexplicably make it through the cold. Even some humans have come back from what seemed an icy demise, for example the Canadian toddler Erica Nordby. In 2001, Nordby’s heart stopped beating for two hours and her body temperature dropped to 61 degrees Fahrenheit before rescuers found her and brought her back to life. Apparent miracles like these inspired Roth to hunt for the biological mechanisms at work.
This study did not freeze humans. Instead, Roth looked for a common life-preserving link in two frozen organisms very different from each other. He chose the nematode embryo and the yeast cell, and found that successful resuscitation in both organisms required extreme oxygen deprivation before freezing.
It’s an earthworm so mysterious, people compare it to the Loch Ness Monster. Rarely sighted since the 1980’s, the giant Palouse earthworm was said to grow almost three feet long, smell like lilies, and spit at predators. It was so elusive, that some even doubted its existence–but now, a team of conservationists from the University of Idaho has found several of these mysterious creatures in a prairie field.
But what a let down it was.
Contrary to popular claim, the earthworms did not smell like lilies or spit at their predators. They weren’t even particularly giant, causing lead researcher Jodi Johnson-Maynard to remark: “One of my colleagues suggested we rename it the ‘larger than average Palouse earthworm'” [The Telegraph].
The team started combing the prairie region between Idaho and Washington state last summer in search of the Palouse earthworms. It was researcher Karl Umiker who eventually struck gold–or in this case, worm. Umiker used a tool called an electroshocker, in which electricity is passed through a number of electrodes that are stuck in the soil. Umiker was “shocking” a fragment of unploughed prairie when two giant earthworms emerged from the soil–a juvenile and an adult.
At the bottom of the Baltic Sea, history sits largely intact. Because shipworms don’t care for these cold, low-salt waters, shipwrecks can endure for centuries without great decay. The Vasa, a famous Swedish warship that sank in Stockholm harbor in 1628, was in terrific condition when engineers raised it from the depths more than 300 years later. But, scientists now warn, those conditions could be coming to an end due to global warming.
Shipworms, which can obliterate a wreck in ten years, have already attacked about a hundred sunken vessels dating back to the 13th century in Baltic waters off Germany, Denmark, and Sweden, reported study co-author Christin Appelqvist [National Geographic News]. Now, Appelqvist says, their range is beginning to extend beyond those areas into the northern part of the Baltic. That could threaten close to 100,000 shipwrecks scattered across the bottom of the sea.
Feel like teaching a lesson to that pinhead-sized worm that’s been bothering you? According to a study in the Journal of the American Chemical Society, a material called dithienylethene plus a blast of UV light can stop a worm in the midst of its worming, rendering it temporarily paralyzed.
The researchers fed a light-sensitive material — a “photoswitch” known as dithienylethene — to the transparent worms. When exposed to ultraviolet rays, the molecule turned blue and the worms became paralyzed. Using visible light instead made the chemical turn colorless and the paralysis ended [LiveScience]. Scientists aren’t sure why the transparent nematodes became paralyzed, but they know dithienylethene changes shapes and suspect it interferes with the worm’s energy-producing metabolic pathways. Repeated cycles of UV-induced paralysis actually killed some of the worms.
Unsurprisingly, news of this worm stun-gun led to longing for Star Trek-style phasers, and the scientists, though skeptical, were good sports about it. As lead researcher Neil Branda said tactfully: “I’m not convinced there’s a legitimate use of turning organisms on and off in terms of paralysis, but until somebody tells me otherwise, I’m not going to say that there isn’t an application” [BBC News].
But while phasers remain a fantasy, light-activated materials certainly have a future in medical research. Light-activated drugs could be used to activate tumour-killing drugs once they reach a particular location in the body. Similar chemicals have been used before, but have required a steady supply of light – often harmful UV bandwidths – to stay active. The new compounds, known as diarylethenes, could be more useful because they can be switched on and off with a single light pulse, Branda says [New Scientist].
80beats: Lasers Write False, Fearful Memories into the Brains of Flies
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80beats: In Worms, a New Theory on Aging
Discoblog: New “Worm Charming” Champion Sets World Record
Image: Wiki Commons / Yonatanh
A tiny worm has developed a compelling system for survival: It avoids trouble and sickness. A single genetic change in the tiny worm Caenorhabditis elegans compels some worms to stay away from harmful bacteria and others to eat the microorganisms [Science News]. While some researchers believe that the healthier worms also have some innate immunity to the bacteria, a new study shows definitively that a gene controls their behavior and keeps them from ingesting substances that will do them harm.
As reported in Science [subscription required], researchers first noted that a Hawaiian population of C. elegans had less resistance to harmful bacteria than the standard laboratory worms. A genetic study revealed that the Hawaiian worms have a different version of a gene called npr-1, which causes them to produce less of a protein that senses signals from neurons. When researchers tweaked the standard lab worms to have the same npr-1 mutation, those worms were also more susceptible to infection, indicating that the single gene was somehow responsible.
A genetic study of worms has challenged the prevailing theory of aging, which holds that organisms eventually break down and die as a result of wear-and tear on their bodies. Researchers have found that certain genes in the worms are genetically programmed to stop functioning as the worm ages; while there’s no guarantee that a similar process takes place in humans, the results nevertheless give hope that science eventually may find a way to stop or reverse the aging process [HealthDay News].
Researchers have thought that aging is due to damage inflicted on our cellular DNA (genetic material) by factors such as smoking, disease, the sun’s ultraviolet rays and chemically reactive molecules called free radicals, which are produced when our cells make energy. [This study] suggests instead that a combination of factors is at play—that in addition to [environmental factors], there are also certain genes that may carry instructions to start the aging process [Scientific American].