By James Gallagher - Health and science correspondent, BBC News
Spider Gains
If we want to stop malaria from killing more than 400,000 people every year, we’ll need to stop mosquitoes — the irksome insects are the primary transmitter of the deadly disease.
To that end, researchers from the University of Maryland (UMD) genetically modified a fungus to produce a spider toxin that quickly kills mosquitoes. And in an out-of-lab trial, the fungus reduced a mosquito population by more than 99 percent, according to NPR — though the team’s controversial use of genetic engineering has some worried the method is too dangerous for the real world.
Killer Fungus
According to a paper published Thursday in the journal Science, the fungus the UMD researchers modified kills mosquitoes in the wild — but it isn’t particularly fast, meaning the insects might have time to infect someone with malaria before meeting their demise.
To give the fungus a boost, the team engineered it to produce a toxin derived from the venom of the Australian Blue Mountains funnel-web spider, which kills mosquitoes far more quickly. The team then tested the fungus in a “MosquitoSphere,” a screen-enclosed setting in West Africa designed to mimic a village.
“Simply applying the transgenic fungus to a sheet that we hung on a wall in our study area caused the mosquito populations to crash within 45 days,” researcher Brian Lovett said in a news release. “And it is as effective at killing insecticide-resistant mosquitoes as non-resistant ones.”
Calculated Risk
This was the first time anyone has tested a transgenic method for combating malaria outside of a lab setting, according to the news release. But while the fungus may have been effective, some worry that releasing a genetically engineered organism into the wild could cause unforeseen problems.
“This study raises several urgent concerns,” Dana Perls of the environmental group Friends of the Earth told NPR. “Genetic engineering of fungus could have problematic negative public health impacts and unpredictable ripple effects on ecosystems, affecting pollinators, bats, and bees. Like with all genetic engineering, this needs to be addressed with great caution.”
READ MORE: Scientists Genetically Modify Fungus To Kill Mosquitoes That Spread Malaria [NPR]
More on malaria: Scientists Wiped out a Mosquito Population by Hacking Their DNA With CRISPR
By Sarah Gibbens Published May 30, 2019
“There's this romantic idea of the remote tropical beach, clean and pristine….that kind of beach doesn't exist anymore.”
Only a year ago, streams of lava gurgled from Hawaii's Kilauea volcano, blocking roads and inching across fields. It eventually reached the ocean where the intensely hot lava hit cold seawater and burst into tiny shards of glass and rubble: brand new sand.
Eventually, new beaches formed, like Pohoiki, a black sand beach that stretches for 1,000 feet on Hawaii's Big Island. Scientists based in the area aren't sure if the beach formed quickly after the volcano began erupting in May 2018 or slowly as the lava began to simmer down in August, but based on samples taken from the newborn beach, they know it's already polluted—covered with hundreds of tiny pieces of plastic. Pohoiki adds to the growing body of evidence that plastic is most likely ubiquitous on beaches: even ones that look virgin.
Pohoiki adds to the growing body of evidence that plastic is most likely ubiquitous on beaches: even ones that look virgin.
Testing the waters
Microplastic is smaller than five milimeters and rarely larger than a grain of sand. To the naked eye, Pohoiki looks pristine.
“It's gorgeous,” says Nic Vanderzyl, the University of Hawaii at Hilo student who discovered the beach's plastic.
Vanderzyl saw the new beach as an opportunity to study new sediment that was perhaps untouched by human influence. He collected 12 samples from various beach spots. Using a solution of zinc chloride, which is more dense than plastic but less dense than sand, he was able to separate the two by forcing plastic to float to the top while the latter sank. The separation method was published in the journal Environmental Pollution in 2017.
On average, Vanderzyl found 21 plastic bits per every 50 grams of sand. Most of them, he says, were microfibers, the hair-thin fibers that shed from commonly used synthetic textiles like polyester or nylon. They enter the water via wastewater flushed from washing machines or simply from swimmers plunging into the sea.
Steven Colbert, a marine ecologist and Vanderzyl's academic mentor, says the plastic would have likely washed up with waves and been left on the beach as tiny grains of sand comb through it. Compared with samples taken from two other neighboring beaches that were not formed by volcanoes, Pohoiki has about 30 to 50 percent of the plastic they have.
Vanderzyl and Colbert plan ongoing monitoring of Pohoiki to measure whether the amount of plastic increases or stays the same.
-An end to pristine beaches
“I didn't want to find it,” Colbert says of the microplastic in Vanderzyl's samples, “but I really wasn't surprised.”
“There's this romantic idea of the remote tropical beach, clean and pristine like the beach Tom Hanks washed up on [in the movie Castaway],” says Colbert. “That kind of beach doesn't exist anymore.”
Plastic, including microplastics, has washed ashore on some of the world’s most remote beaches, uninhabited by humans.
Scientists have often likened the current state of the ocean to a plastic soup. Microplastics are so prolific that they rain down from the sky in remote mountain locations and turn up in most of our table salt.
It's still unclear how this excess of plastic will affect marine ecosystems, but scientists suspect it may have dangerous consequences for wildlife and human health. Numerous times, large marine mammals like whales have washed ashore with guts full of plastic, but scientists have recently found that even larval fish are eating microplastic in their first days of life.
And unlike larger plastic items like bags and straws that might be grabbed and tossed in the trash, microplastics are is simultaneously abundant and invisible. One study published earlier this month found that beach clean-ups often leave behind millions of pieces of plastic.
Conservation groups like the Hawaii Wildlife Fund have teamed up with universities to
develop beach cleaning contraptions that essentially act like a vacuum, sucking up sand and separating out the microplastics. But the machines’ bulk, cost, and the tendency to scoop up microscopic life as well all mean they can be used to clean only the worst polluted beaches.
Though already filled with plastic, Pohoiki has a long way to go before it can rival places like Hawaii's famous “trash beach.”
Vanderzyl hopes to return to Pohoiki in the coming year to see if or how the beach changes, but already, Colbert says, his early research shows that beach pollution is now instantaneous.