To kill drug-resistant bacteria, “last-resort” antibiotics borrow a tactic from Medusa’s playbook: petrification. New high-resolution microscope images show that a class of antibiotics called polymyxins crystallize the cell membranes of bacteria. The honeycomb-shaped crystals that form turn the microbes’ usually supple skins of fat molecules into thin brittle sheets , researchers report October 21 in Nature Communications . When the petrified membranes break, the bacteria die. The finding was a total surprise, says Sebastian Hiller, a structural biologist at the University of Basel in Switzerland. Hiller, biophysicist Selen Manioğlu and their colleagues had been using the antibiotics as a control for a different experiment. When the researchers turned on their microscopes, “we saw these waffles,” Hiller says. “I immediately recognized, wow, this must be something special.” Polymyxin antibiotics like colistin were discovered in the 1940s and are now used as a powerful last-ditch def
Superconducting temperatures have risen by about 250 degrees since the 1970s, but are still too cold to enable practical technologies. from Science News https://ift.tt/cbVHa6t via
Inspired by how ants move through narrow spaces by shortening their legs, scientists have built a robot that draws in its limbs to navigate constricted passages. The robot was able to hunch down and walk quickly through passages that were narrower and shorter than itself , researchers report January 20 in Advanced Intelligent System s. It could also climb over steps and move on grass, loose rock, mulch and crushed granite. Such generality and adaptability are the main challenges of legged robot locomotion, says robotics engineer Feifei Qian, who was not involved in the study. Some robots have specialized limbs to move over a particular terrain, but they cannot squeeze into small spaces ( SN: 1/16/19 ). “A design that can adapt to a variety of environments with varying scales or stiffness is a lot more challenging, as trade-offs between the different environments need to be considered,” says Qian, of the University of Southern California in Los Angeles. For inspiration, researchers
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