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Gizmorama - July 12, 2017

Good Morning,

It appears that scientists have successfully recovered human DNA from mosquitoes. What about Dino DNA? Jurassic Park doesn't seem so far-fetched now, does it?

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,

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*-- Scientists recover human DNA from mosquitoes --*

New research proves human DNA can be successfully extracted from mosquitoes and sequenced two days after feeding.

Forensic scientists have previously suggested suspects could be placed at the scene of the crime if their DNA was recovered from a local mosquito population. But until now, researchers weren't sure how long it takes mosquitoes to digest human blood and render DNA unrecognizable.

The new research -- published this week in the journal PLOS ONE -- suggests human DNA remains intact inside a mosquito's stomach for at least two days after consumption.

"We asked several volunteers to let mosquitoes bite them," Yuuji Hiroshige, a forensic scientist at Nagoya University in Japan, said in a news release. "After allowing the mosquitoes to digest the blood for a certain amount of time, we extracted the human DNA and used PCR techniques to amplify the sample for quantification and genotyping."

Scientists used polymerase chain reaction to amplify DNA fragments in the mosquito blood. The technique allowed scientists to identify DNA fragments belonging to the study participants.

After three days, researchers found no recognizable DNA fragments, as the human blood had been completely digested.

"Ours is the first study to systematically apply modern DNA profiling techniques to the challenging forensic analysis of mosquito blood meal," said lead researcher Toshimichi Yamamoto. "We hope this will help crime scene investigators collect reliable evidence that could be used to guide investigations and support convictions. Although we need to take some steps to improve our methods and obtain more data, with more accurate quantification methods, we might be able to estimate the time after mosquitoes' blood feeding with even greater accuracy."

*--- Scientists develop more eco-friendly way to synthesize spider silk ---*

Scientists at the University of Cambridge have developed a new, more eco-friendly method for synthesizing spider silk. The extra stretchy, super strong fibers could be used in textiles, sensors and other technologies.

The synthetic spider silk fibers, which look like mini bungee cords, are made of mostly water. Unlike previous synthesis methods, the new technique doesn't require toxic solvents. The new method is also less energy intensive and can be performed at room temperature.

The new synthetic silk is spun from a hydrogel, composed of 98 percent water and 2 percent silica and cellulose. The combination of silica and cellulose feature molecular "handcuffs" called cucurbiturils, which hold the gel's molecules together and allow threads to be pulled from the gel solution.

Water evaporates from the pulled threads leaving behind a stretchy, strong fiber.

"Although our fibers are not as strong as the strongest spider silks, they can support stresses in the range of 100 to 150 megapascals, which is similar to other synthetic and natural silks," Darshil Shah, a material scientist in Cambridge's architecture department, said in a news release. "However, our fibers are non-toxic and far less energy-intensive to make."

The threads are held together by unique molecular structures, not covalent bonds.

Researchers detailed their breakthrough method this week in the journal PNAS.

"When you look at these fibers, you can see a range of different forces holding them together at different scales," said lead study author Yuchao Wu, a doctoral student in Cambridge's chemistry department. "It's like a hierarchy that results in a complex combination of properties."

Not only are the new fibers stronger than previous interactions of synthetic spider silk, they also can absorb more energy -- like a bungee chord.

"We think that this method of making fibers could be a sustainable alternative to current manufacturing methods," said Shah.


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