January 07, 2019

Good Morning,

Science is afoot! Check out the two remarkable stories I have selected for your reading pleasure below.

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

Until Next Time,
Erin

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*-- Activating large silent genes allows bacteria to synthesize new molecules --*

When researchers stripped away repressors thwarting the expression of big, silent genes in Streptomyces bacteria, they unlocked the genetic building blocks of several new molecules.

Because Streptomyces bacteria synthesizes several molecules used in antibiotics and anti-cancer drugs, scientists hope their work will lead to the discovery of new therapeutic agents.

"There are so many undiscovered natural products lying unexpressed in genomes. We think of them as the dark matter of the cell," Huimin Zhao, a chemical and biomolecular engineering professor at the University of Illinois, said in a news release. "Anti-microbial resistance has become a global challenge, so clearly there's an urgent need for tools to aid the discovery of novel natural products. In this work, we found new compounds by activating silent gene clusters that have not been explored before."

Small silent gene clusters have previously been unmuted using CRISPR technology, but larger silent gene clusters have been difficult to unlock.

To free up the large gene clusters in Streptomyces, researchers inject the bacteria with copies of the target DNA fragments. Scientists dubbed the copies transcription factor decoys. Zhao deployed the clones in an effort to lure away the silencing agents. Their subterfuge worked.

"Others have used this similar kind of decoys for therapeutic applications in mammalian cells, but we show here for the first time that it can be used for drug discovery by activating silent genes in bacteria," said Zhao.

According to Zhao, the new method -- described in the journal Nature Chemical Biology -- doesn't disrupt the natural genome.

"It's just pulling away the repressors," he said. "Then the genes are expressed naturally from the native DNA."

The decoys deployed by Zhao and his colleagues enabled the bacteria's previously silenced gene cluster to produce eight new molecules, but so far, scientists have identified the structure of just two and described only one in detail.

In follow up studies, scientists plan to precisely describe the structure and characteristics of all eight. Researchers also plan to test whether any of the new molecules boast anti-microbial, anti-fungal, anti-cancer or other potentially useful biological properties.

*-- New metamaterial offers exceptional sound transportation --*

Researchers have developed a new metamaterial with a robust acoustic structure. The novel material transports sound along its edges and concentrates it at its corners.

Material scientists at the City University of New York and at the City College of New York designed the metamaterial with the help of a mathematical field called topology. Topology is the study of objects unaffected by continuous deformations.

A straw and a donut, for example, both having a single hole, are topologically equivalent. Both objects could be contorted to form the other other without adding new holes.

The principals of topology first inspired the team of material scientists to design materials that only carry electric currents along their edges. According to scientists, the topological nature of their band gap makes these materials' conductivity resistant to disruption by noise or imperfection.

"There has been a lot of interest in trying to extend these ideas from electric currents to other types of signal transport, in particular to the fields of topological photonics and topological acoustics," Andrea Alù, director of the Photonics Initiative at City University's Advanced Science Research Center, said in a news release. "What we are doing is building special acoustic materials that can guide and localize sound in very unusual ways."

To build their new metamaterial, Alù and his research partners used a 3D printer to create a series of tiny trimers, a ring formed by three acoustic resonators. Scientists affixed the trimers to form a triangular lattice.

The symmetry of the trimers and chiral symmetry of the larger lattice structure yielded robust acoustic properties derived from the topology of the metamaterial's acoustic bandgap.

When sound is played at frequencies outside the band gap, the sound is made to travel through the bulk of the metamaterial, but when frequencies within the band gap are played, the sound moves along the edges to the metamaterial's corners.

The metamaterial's unique acoustic properties aren't disrupted by imperfections.

"You could completely remove a corner, and whatever is left will form the lattice's new corner, and it will still work in a similar way, because of the robustness of these properties," Alù said.

Researchers described their feat in the journal Nature Materials, and are now trying to build upon their latest findings by constructing more complex metamaterials with unique acoustic qualities.

"We're showing, fundamentally, that it is possible to enable new forms of sound transport that are much more robust than what we are used to," Alù said. "These findings may find applications in ultrasound imaging, underwater acoustics and sonar technology."