Blogs / 80beats

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].

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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.

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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].

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