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Scientists bioengineered salmonella that can kill the deadliest brain cancer, observed bacteria in a slime that “communicate with one another like neurons in the brain,” and tied the world’s tiniest knot. We’ll keep you in the loop.
Bioengineers at Duke University have tweaked the DNA of a salmonella bacteria strain that typically causes food poisoning and then used the modified bugs to attack glioblastoma, the deadliest form of brain cancer. The team engineered the bacteria to penetrate the protective blood-brain barrier and turned the bacteria “into a cancer-seeking missile that produces self-destruct orders deep within tumors.” That’s because the genetic changes compelled the microbes to produce a pair of compounds called Azurin and p53 that tell cells to commit suicide. Duke reported that tests in rats with “extreme cases of the disease” extended the lives of 20 percent of the population by 100 days — roughly equivalent to 10 human years — and sent their tumors into complete remission. “A major challenge in treating gliomas is that the tumor is dispersed with no clear edge, making them difficult to completely surgically remove,” said Ravi Bellamkonda, dean of Duke’s Pratt School of Engineering and corresponding author of the paper. “So designing bacteria to actively move and seek out these distributed tumors, and express their anti-tumor proteins only in hypoxic, purine-rich tumor regions is exciting.” The results were published in the journal Molecular Therapy – Oncolytics.
Engineers at Vanderbilt University developed a “DNA duplicator small enough to hold in your hand.” The device could enable doctors to spot disease quickly before symptoms appear and identify Ebola, malaria and dengue fever in a single sample in areas far from hospitals. It could be also used for forensic research and other applications. The team calls the approach “adaptive PCR.” PCR, or polymerase chain reaction, is a key component o DNA analysis. Chemist Kary Mullis invented PCR, or polymerase chain reaction, in 1983, and the method earned him a Nobel Prize 10 years later.The approach is now a key component of DNA analysis. But the technique still requires very high sample quality and a controlled environment. Adaptive PCR is easier to use. It relies on a strand of fluorescent DNA to monitor and control the reactions during PCR. “These advantages have the potential to make PCR-based diagnostics more accessible outside of well-controlled laboratories, such as point-of-care and field settings that lack the resources to accurately control the reaction temperature or perform high quality sample preparation,” the researchers said. Their findings appear in the journal Analytical Chemistry.
Biologists at the University of California, San Diego observed colonies of bacteria that “communicate with one another like neurons in the brain” and “resolve social conflicts within their communities.” The team said these biofilms made of diverse bacteria “create what are essentially electronic advertisements … by sending long-range electrical signals to other bacterial species.” They used these ads to recruit new microbes to join them. “Our study shows that bacteria living in biofilm communities do something similar to sending electronic messages to friends,” said Jacqueline Humphries, a UC San Diego doctoral student and the first author of the paper. “In fact, the mechanism we discovered is general. We found that bacteria from one species can send long-range electrical signals that will lead to the recruitment of new members from another species. As a result, we’ve identified a new mechanism and paradigm for inter-species signaling.” Biofilms range from teeth plaque to slime and pond scum and can be highly resistant to chemicals and antibiotics. The study’s results, which were published in the journal Cell, could lead to new ways to fight them.
Researchers at Harvard University built a “brain-on-a-chip” device that mimics how three regions of the brain are connected. The model “allows researchers to study how diseases like schizophrenia impact different regions of the brain simultaneously,” according to a Harvard news release. “When the cells are communicating with other regions, the cellular composition of the culture changes, the electrophysiology changes, all these inherent properties of the neurons change,” said Harvard’s Ben Maoz, co-first author of the paper. “This advance will not only enable the development of therapeutics, but fundamental insights as to how we think, feel, and survive,” added Harvard bioengineering professor Kit Parker,
Scientists at the University of Manchester have tied the tightest knot ever. They say that the achievement could lead to a new generation of supermaterials. “Some polymers, such as spider silk, can be twice as strong as steel so braiding polymer strands may lead to new generations of light, super-strong and flexible materials for fabrication and construction,” according David Leigh, a professor at Manchester’s School of Chemistry. The knot has eight crossings on a loop made from 192 atoms and just 20 nanometers long. “Tying knots is a similar process to weaving, so the techniques being developed to tie knots in molecules should also be applicable to the weaving of molecular strands,” Leigh said. “For example, bulletproof vests and body armor are made of Kevlar, a plastic that consists of rigid molecular rods aligned in a parallel structure — however, interweaving polymer strands have the potential to create much tougher, lighter and more flexible materials in the same way that weaving threads does in our everyday world.”
Top image: An illustration of a drug-resistant biofilm. Image credit: Getty Images