Salt infusion a remedy for damaged cells?

It turns out that a dash of salt can really do a body, especially a tail, some good. An infusion of sodium helped tadpoles regenerate amputated tails, according to a paper in the Journal of Neuroscience. The finding is significant because further study could help scientists develop medical treatments for spinal cord damage or limb loss in humans, the study’s authors wrote.

The scientists administered a drug to the tadpoles that rushed an influx of sodium ions to the injured cells.  They found that a salt stimulus prompted regeneration as late as 18 hours after amputation. Tissues normally do not regenerate so many hours after the damage is done, and particularly after scar tissue forms.

Although young tadpoles can naturally regenerate lost tails, this ability diminishes with age. Sodium ions also appear to reactivate this ability, said Michael Levin, a biologist at Tufts University and one of the study’s authors.

One particular ion channel in the tadpoles, which is called NaV1.2, is responsible for transporting sodium to damaged cells for the purpose of regeneration, the researchers discovered. When this channel is blocked, thereby inhibiting sodium that would otherwise naturally travel to the damaged cells, there is regenerative failure.If a regenerative treatment could be developed for humans, it would transform the medical field.

When a dog’s dish seems half-empty

Dogs can be worried and pessimistic just like people, researchers report in a new study in Current Biology. Scientists say dogs that exhibit anxiety when left home alone by their owners may have bigger problems – they may be in a permanent bad mood. This pessimistic outlook may not otherwise be easily apparent in a dog’s other characteristics, like running speed or learning ability, the study reports.

Dogs are similar to humans in the role that emotional state plays in decision making, said Dr Michael Mendl, a veterinary scientist at the University of Bristol and the study’s lead author. Researchers looked at 24 dogs in shelters in Britain. They placed the dogs in isolated settings and observed their reactions – many barked, jumped on furniture and scratched at the door. Then they placed bowls in two rooms.

One bowl contained food, while another was empty. After training the dogs to understand that bowls can sometimes be empty, and sometimes full, they began to place bowls in ambiguous locations.

Dogs that quickly raced to the locations were more optimistic, and in search of food. Those that did not were deemed pessimistic. The more separation anxiety a dog expressed while in isolation, the more likely the dog was to have a pessimistic reaction, the researchers found.

Joints key to bats’ complicated flight

The scientific order for bats, Chiroptera, translates to “hand wing.” Like human hands, bat wings are fleshy and have myriad joints. Bird wings have only a few joints, and those of winged insects contain a single joint. Now, using slow-motion cameras, researchers have found that because of these joints, bat flight is significantly more complicated than bird flight.

The research appears in The Journal of Experimental Biology. Scientists placed bats in wind tunnels, creating a treadmill-like space where they flew in place. They then studied the wake left by the bats’ fluttering wings. The bats each left four whirling masses in the air as they flew. The strongest vortex came from the wing’s tip and lasted through the end of each upstroke made by the bats.

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