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Hank: We’ve got a whole lotta holes in this episode of SciShow News! Human nose holes, the unexpected source of a new antibiotic... and blue holes, which go deeper than ever before.

So let’s start with the blue kind.. cuz you probably don't know what I'm talking about. Chinese scientists have reportedly found the deepest blue hole – an underwater cavern or sinkhole, named for its deep blue color compared to the surrounding shallow water. Using an underwater robot, researchers from the Sansha Ship Course Research Institute for Coral Protection plumbed the depths of Dragon Hole, in the Paracel Islands in the South China Sea. They measured the hole to be a whopping 300 meters deep – deep enough to submerge the Eiffel Tower! Their findings still need to be independently confirmed by other scientists working in the field. But if true, this’ll smash the previous record, held by Dean’s Blue Hole in the Bahamas by nearly a hundred meters.

Blue holes are basically underwater caverns with a big entrance on top. They’re usually found in areas with lots of limestone or other carbonate rocks, which are slightly water soluble under the right conditions. So if they’re exposed to acidic rain, or flowing water, some water can seep below the surface and erode the rock, forming a hidden underground cavern. If the top layer gets too thin, the ceiling can collapse, leaving a deep well known as a sinkhole. And if sea levels then rise, like they did after the last ice age, you’ve got yourself a blue hole.

That’s generally what happens, but each blue hole has a different origin story – just like caves on land. Also, the role of things like climate and environmental microbes aren’t well understood. The researchers plan to keep studying Dragon Hole, and might figure out how it formed, but that’s not the only reason to study it: There’s life, too!

The researchers found 20 species that called Dragon Hole their home – but they all lived in the top 100 meters or so. Below that, oxygen levels plummeted, and apparently there wasn’t much life. Now, it’s not impossible to find life in the deep ocean – we’re finding weird new species every year, some living kilometers beneath the waves. In the future, maybe scientists could find some unique stuff in the depths of Dragon Hole, whether it’s specialized microbes or fossils in the sediment.

But human nose holes have their own interesting microbes too: Researchers from the University of Tübingen have discovered a brand new antibiotic. It’s a peptide molecule they named lugdunin, which can kill a whole range of harmful bacteria. This includes MRSA – a superbug strain of Staphylococcus aureus that kills an estimated 11,000 Americans each year, by infecting the skin, lungs or bloodstream. This is a really big deal, because right now we’re not finding enough new antibiotics to fight off multidrug-resistant bacteria. Lugdunin is one of the first antibiotics extracted from human microbiota bacteria that live in and around our bodies – rather than from soil bacteria, or other sources.

Specifically, it’s produced by a species called S. lugdunensis. The researchers were curious about this microbe after comparing the nasal microbiota of people with and without S. aureus. They found that people who had S. lugdunensis in their noses were nearly six times less likely to also have S. aureus up there. The reason? Well, when the researchers stuck them on a petri dish together, they found that S. lugdunensis eliminates S. aureus even when outnumbered ten to one! By analyzing its genome, the scientists pinned down the molecule responsible for all that carnage: lugdunin.

They aren’t exactly sure how it works yet, but it might have to do with breaking down energy resources that the bacteria need to do... like, everything. Our bodies are like battlefields – the bacteria are fighting for space and nutrients, using tricks like lugdunin to help kill off the competition. The researchers hope this bacterium’s killer compound is one we can use for ourselves, with some careful development. We don’t just want to go sticking S. lugdunensis up people’s noses, because it can cause infections if given the chance, but maybe scientists could transfer the antibiotic gene to a completely harmless bacterium, so it can produce the chemical for us. Or if we can develop a prescription drug, it could help people who need lots of surgeries or with lowered immune systems – situations where the opportunistic S. aureus can spread uncontrollably.

Now, lugdunin may be promising, but it doesn’t kill off all kinds of bacteria, and it’s a long way off from hospital use. Even for a molecule around 10% of us have up our nostrils right this moment, drug development takes years to be safe and effective. But understanding more about how bacteria interact inside us – whether it’s helping each other or competing for space – could possibly lead to even more antibiotic discoveries... right under our noses.

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