Lef Apostolakis, Author at żěè¶ĚĘÓƵ Science news and science articles from żěè¶ĚĘÓƵ Tue, 25 Apr 2017 09:37:44 +0000 en-US hourly 1 https://wordpress.org/?v=7.0.1 242057827 Plastic-munching caterpillars may show us how to dissolve waste /article/2128659-plastic-munching-caterpillars-may-show-us-how-to-dissolve-waste/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS /article/2128659-plastic-munching-caterpillars-may-show-us-how-to-dissolve-waste/#respond Mon, 24 Apr 2017 16:00:18 +0000 /?post_type=article&p=2128659 Caterpillar on plastic sheet
Grub is served
César Hernández/CSIC

Caterpillars could hold the key to our growing problem of plastic waste. While doing some routine beehive maintenance, a team of researchers in Spain has chanced upon one type of caterpillar that seems to have a taste for the stuff.

Federica Bertocchini at the Institute of Biomedicine and Biotechnology of Cantabria was picking honeycomb moth caterpillars out of a beehive and placing the beeswax-eating pests in a plastic bag for disposal. After a while she found that the caterpillars had broken loose and were milling everywhere. She and her team later confirmed the caterpillars can eat through plastic, and they now want to develop a quick way of breaking down polyethylene – used to make plastic bags – with enzymes from the caterpillars.

The team found that 100 caterpillars of the Galleria mellonella moth can riddle a supermarket shopping bag with holes in under an hour, and can consume 92 milligrams of plastic in half a day – that’s just over 3 per cent of a shopping bag. “That’s quite fast,” says Bertocchini, considering that it takes at least 100 years for one to decompose naturally.

Read more: Plankton snacking on plastic caught on camera for the first time

To make sure the caterpillars were actually digesting the plastic, the team ground some of them up and spread a thin layer of the paste on a polyethylene film. Within 14 hours and after some reapplications, the paste had broken down 13 per cent of the plastic. The team also found traces of ethylene glycol, a sign of polyethylene breakdown.

“Our study is the first scientific work to show that this species eats plastic with the chemical depolymerisation of polyethylene,” says Bertocchini. Such an ability might be down to the caterpillars harbouring certain gut microbes.

Wei-Min Wu from Stanford University, who has studied various plastic-eating species, says the results are exciting. But he says the paste has produced a much higher biodegradation rate than anything seen in polyethylene-degrading bacteria isolated so far, suggesting that what goes on in the caterpillar’s gut is more complicated.

Read more: Bacteria found to eat PET plastics could help do the recycling

Bertocchini is hoping that a single enzyme is what is breaking down the plastic. “If this is the case, I can picture a scenario in the future where we can isolate it, produce it on a large scale and use that to biodegrade plastics.” She has founded a biotech company with one of her co-researchers, but they don’t yet have the funds to test the idea.

They’re not the only ones working on this. BioCellection, start-up based in San Jose, California, is hoping to launch a pilot plastic waste-processing plant by 2020. Their plan involves chemically treating plastics to make them easier for bioengineered bacteria to digest.

Read more: Plastic Age: How it’s reshaping rocks, oceans and life

In the meantime, it’s not unreasonable to think we will keep finding organisms that have evolved to digest plastic. But our plastic problem won’t magically go away. On the plus side, neither will these creatures start devouring our precious plastic goods.

“These animals don’t live on plastic,” says Bertocchini. “They eat it to get out of it, or get to the food behind it. If in the future something evolves to exclusively eat plastic, I don’t know. So far it hasn’t happened.”

Current Biology

]]> /article/2128659-plastic-munching-caterpillars-may-show-us-how-to-dissolve-waste/feed/ 0 2128659 First living example of giant ancient mollusc found in the wild /article/2128009-first-living-example-of-giant-ancient-mollusc-found-in-the-wild/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS /article/2128009-first-living-example-of-giant-ancient-mollusc-found-in-the-wild/#respond Mon, 17 Apr 2017 19:00:41 +0000 /?post_type=article&p=2128009 The first known living sample of a giant, ancient mollusc that previously was known almost exclusively by its shells has been recovered from the Philippines. A team of researchers have finally come across a live colony of giant shipworms, or Kuphus polythalamia. Washed-up, empty, elephant tusk-like shells first hinted at the existence of this metre-long animal in the 18th century, and there are a few specimens preserved in ethanol in collections around the world. But no one knew exactly what lay within – until now. at the Ocean Genome Legacy Center at Northeastern University in Boston and his colleagues were made aware of the animal’s potential location in 2010, when a collaborator pointed out a featuring a local trying to eat one for its supposed medicinal properties. “[It was] amazing! I’ve been looking for them for 20 years,” Distel says. “My friend and mentor looked for her whole career.” The TV footage sparked an international search for the giant shipworm. Local researchers embarked on two expeditions, one in 2010 and one in 2011. During the second expedition, they found live specimens of K. polythalamia and transported them to the University of the Philippines to be analysed. “It’s hard not to be amazed when seeing one in the flesh, even if you know nothing about them,” Distel says. “There is no other animal like them.”

Noxious mud

The giant shipworm is the world’s longest bivalve and the only known extant species of its genus. Unlike other shipworm species that typically burrow into and eat driftwood, the giant shipworm inhabits organic rich, noxious mud and doesn’t seem to feed much at all. Instead it relies on symbiotic bacteria in its gills. “Bacterial symbionts have been cropping up in various bivalve families,” says at London’s Natural History Museum, who was not a member of the expedition. “It’s only since the early 1980s that we recognised that bivalves have bacterial symbionts at all.” Finding them in the family that K. polythalamia belong to as well expands this relationship. The bacteria break down the mud’s hydrogen sulfide, which give the shipworm’s habitat a distinct rotten egg smell, and produce organic carbon, feeding their host. The shipworm is so reliant on the bacteria that many of its internal digestive organs have shrank from lack of use.

New addition

This isn’t the only surprise harboured in the giant’s shell. It turns out the giant shipworm is a newer addition to the family tree, rather than an ancient ancestor. “Kuphus was thought to be the most primitive shipworm,” Distel says. “Instead it turns out to have evolved from wood eating shipworms. Its anatomical simplicity is actually the result of specialisation for a new lifestyle rather than the lack thereof.” Though Distel’s team presented their initial findings in 2013, they are only releasing their full results now after vigorous testing, including extensive genome sequencing and the first ever culture of a sulfur oxidizing symbiont. “This is one of those cases where extraordinary claims required extraordinary evidence – and we really hammered this one,” Distel says. ]]> /article/2128009-first-living-example-of-giant-ancient-mollusc-found-in-the-wild/feed/ 0 2128009