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Space Travel Causes Liver Damage in Mice

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Don’t book that trip to Mars just yet: According to a study recently published in the journal PLOS ONE, a quick trip aboard the space shuttle was enough to cause liver disease in mice.

As space technology races ahead, doctors and scientists scurry along, trying to ensure that our travelers will be safe. We know that returning astronauts often experience dizziness, vision problems, weakened immune systems, and more. Yet somehow the liver—which is kind of an important organ—had been more or less ignored. To physicist and biomedical researcher Karen Johnscher of the University of Colorado, this was a pretty big oversight.

So Jonscher and her colleagues sent 15 female mice into orbit aboard STS-135, the last flight of the Space Shuttle Atlantis. Another 15 stayed on Earth as a control group. The rodents’ voyage was a short one, lasting just 13 and a half days. Once the mice had returned, the researchers euthanized all the mice, weighed them, and took samples of their livers.

These samples underwent a battery of tests, from DNA sequencing and metabolomics (looking at small molecules called metabolites) to chromatography and spectroscopy (to analyze the exact chemical makeup of the tissue samples). Sections of liver were examined under high-powered microscopes.

The differences between the two groups of mice were apparent immediately. All the mice had lost some weight, but those that had gone to space lost nearly twice as much as their counterparts on the ground—even though they’d all eaten the same amount of food. And the weight loss came from different types of tissue. Mice on the ground tended to lose more fat, while the shuttle mice lost lean muscle, which left them with a higher percentage of fat in their bodies. The traveling mice also drank 20 percent less water.

Changes were also evident in the rodents’ livers. Shuttle mice were storing more fat there, they had lower levels of Vitamin A, and the trip appeared to have activated harmful cells called hepatic stellate cells. These cells can lead to inflammation and severe fibrosis, or scarring. The mice appeared to be in the early stages of a condition called non-alcoholic fatty liver disease (NAFLD). And all this in less than two weeks.

"It generally takes a long time, months to years, to induce fibrosis in mice, even when eating an unhealthy diet," Jonscher said in a press statement. "If a mouse is showing nascent signs of fibrosis without a change in diet after 13 ½ days, what is happening to the humans?"

The researchers noted that high levels of stress can trigger hormonal changes and inflammation, and that going up in a space shuttle could certainly cause high levels of stress.

"Whether or not this is a problem is an open question," Jonscher said. "We need to look at mice involved in longer duration space flight to see if there are compensatory mechanisms that come into play that might protect them from serious damage."

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Animals
Where Do Birds Get Their Songs?
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Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

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Animals
Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

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