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Scientists Figure Out How Some Probiotics Work

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Unless you’ve been living under a rock for the last few years, you’ve probably heard about the health benefits of yogurt and other fermented foods. Clinical trials have found that probiotics (helpful bacteria) can help ease a range of symptoms. But what they haven’t found is how, exactly, they work. Now scientists writing in the journal Applied and Environmental Microbiology have got a theory.

The bacterial strain called Lactobacillus paracasei DG grows naturally in our mouths and guts. It’s also a common ingredient in probiotic supplements and so-called functional foods like probiotic yogurt. We’re happy to buy it and consume it, but we don’t know what makes it tick.

Researchers at Italy’s Università degli Studi di Milano and the University of Huddersfield in the UK theorized that L. paracasei DG was secreting some strange chemical compound called an exopolysaccharide (EPS). They searched through the bacterium’s DNA and, sure enough, found genes that make EPS.

The next step was to figure out what kind of EPS it was and what it did. They conducted chemical tests and nuclear magnetic resonance to examine the EPS at a molecular level. They found that a large portion of the compound was made of rhamnose, a sugar commonly found in probiotic strains.

Next, the team administered the EPS to living human immune cells and watched to see how they would react. Because probiotics are often used to ease symptoms of inflammation, it might be expected that the EPS would be a calming influence, but the opposite was true: The presence of the compound triggered a release of inflammatory chemicals from the immune cells.

Coauthor Andrew P. Laws says this seemingly counterintuitive finding actually makes a lot of sense. "We have evidence that our polysaccharides bind to and mildly activate the receptors which release pro-inflammatory messengers," he said in a statement. "We believe that this generates a lesser inflammatory response than what would occur if the same receptors were activated by pathogenic bacteria."

It’s a strange strategy, but it’s not completely unheard of. Scientists studying the “mind-control” germ Toxoplasma gondii recently reported that the parasite uses a very similar technique to elude detection within the body of its host.

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This Living Wallpaper Uses Bacteria to Generate Electricity
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Previously known as the culprit behind some of the worst eyesores in home decorating history, wallpaper may be on the verge of a comeback. As FastCoDesign reports, scientists at Imperial College in London, the University of Cambridge, and Central Saint Martins have pioneered an innovative wall covering made of paper that contains live bacteria. The goal? To use that bacteria to generate electricity.

Here’s how it works. The paper is processed through a common inkjet printer, getting stamped with both conductive ink and then cyanobacteria, a photosynthesizing organism that gathers energy from light sources and turns it into electricity. After being exposed to the light, the paper's ink is able to conduct energy from the bacteria. The sample used—paper roughly the size of an iPad—powered a small LED bulb and digital clock via energy collected over the course of 100 hours.

Researchers at Imperial and their colleagues at the University of Cambridge and Central Saint Martins say the applications for “living wallpaper” are numerous. It could be used to monitor indoor air quality by powering sensors; in health care settings, small samples could monitor patients with conditions like diabetes. If enough energy could be harvested, it might be able to power larger devices or even charge phones—all of it disposable and biodegradable.

The project will next attempt to scale the paper panels up in size to allow for greater photosynthesis productivity while cleverly disguised as home decoration.

[h/t FastCoDesign]

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Dirty Money: The Cash In Your Wallet Is a Magnet for Germs
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If an item is handled by the public, whether it's a library book, a subway pole, or an ATM, you can count on it being filthy. One of the worst offenders is something most people carry around wherever they go: money. As TIME reports, a new study confirms that paper money is a magnet for germs and other microorganisms.

For their paper, which appears in the journal PLOS One, researchers swabbed dozens of $1 bills collected from New York City banks over the course of 2013. The results showed microbes from numerous sources living within the fibers. Most came from the human body, like skin bacteria, oral bacteria, and even vaginal bacteria. But non-human DNA was also prevalent. In the summer, researchers were most likely to find traces from pets like dogs and horses, while microbes from indoor fungi were more common in the winter. Skin break out lately? The bacteria to blame for acne were the most common microorganisms detected.

That list alone is enough to make you feel squeamish when leafing through your wallet, but it doesn't end there. American paper currency is 75 percent cotton and 25 percent linen; this composition makes it a cozy environment for other microorganisms like viruses. According to SmartMoney, the flu can survive on paper money for more than 10 days under the right conditions. E. coli and salmonella have also been detected on paper bills.

While these facts make a good case for washing your hands after each transaction, there's no reason to make the full switch to plastic. The same properties that make money such a good home for bacteria also make it hard to spread those germs to people. When microbes settle into the woven material of a dollar, they tend to stay there, even when you take it out and pass it to someone else. And if some microbes do rub off on you, your skin does a great job of keeping them from getting inside your body where they can do real harm. But you should still remember to use hand sanitizer before eating that burger you just paid for.

Unfortunately, objects touched by strangers aren't the only germ-infested environments to be aware of. Here are some of the dirtiest surfaces lurking in your home.

[h/t TIME]

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