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SCIENCE AT WORK Biology Starve and Live Longer In this Caenorhabditis elegans worm, a fluorescent marker shows the nuclei of muscle cells, whose degeneration is slowed by caloric restriction. 12 CNRS INTERNATIONAL MAGAZINE The EZ-10 autonomous shuttle vehicle developed by the Ligier Group. Although driverless cars are a long way off for both technical and regulatory reasons, driverless shuttles, which travel a pre-determined path or within a designated area, are just around the corner. The EZ-10, developed by CNRS researchers1 and the French car manufacturer Ligier, may soon make long walks at airports and hospitals a thing of the past. What sets the EZ-10 apart is its innovative guidance system, which can direct the vehicle on a pre-arranged path, like a train, as well as on a varied itinerary, such as a taxi. “We improved our 2010 model, the Vipa, by adding a second camera for greater visibility, directional lasers to detect unexpected obstacles, and more powerful visual analysis software,” explains Michel Dhome, the project leader. The shuttle has now reached a level of maturity enabling its real experimentation on public or industrial sites. The guidance system first requires a manual trip with a human driver to let shuttle cameras record the itinerary. In subsequent driverless trips, the cameras compare their surroundings with the master recording of the first drive, “replaying” it as closely as possible. This record and replay system is less costly and more reliable than other guidance technologies using Differential Global Positioning System (DGPS) or laser-based radar, which may not function in urban centers or indoors. “For six months in Clermont-Ferrand (central France), the EZ-10 successfully transported passengers from the car park to the entrance of the CHU Estaing hospital 300 meters away,” Dhome adds. “A more ambitious test is underway at Michelin’s research and development center, where a fleet of five automated shuttles are in simultaneous operation, seamlessly deployed by a central computer based on passenger requests.” The EZ-10 garnered excitement at the 2014 Michelin Challenge Bibendum in Chengdu (China) and could be used in a plethora of sites such as industrial centers, pedestrian zones, and amusement parks. ii BY CLEMENTINE WALLACE Surprising though it may be, an extreme diet, bordering malnutrition, extends longevity and reduces age-related diseases in many species, including mammals. But it comes with a downside: fertility loss. In a new study,1 scientists explored the relationship between the two phenomena. “We discovered that, during extreme diet restriction, animals put their reproductive system to sleep as a protective measure. Their energy is thus spent on survival, probably with the goal of delaying reproduction to a more favorable time,” says senior author Hugo Aguilaniu, from the LBMC.2 “If we can trigger one response independently from the other, we might come up with a way to live longer and better.” Tests were performed on roundworms, whose life expectancy is about three weeks. When the researchers reduced the nematodes’ food intake, their lifespan increased by roughly 30%. In vitro experiments revealed that this restriction triggered the secretion of a hormone called “dafachronic acid” (DA). According to the authors, DA then activated what is known as “the TOR pathway,” which regulates reproductive cell proliferation, among other functions. “When DA was secreted, gonads became smaller, as if they were going into hibernation,” says Aguilaniu. Working in mutant worms unable to secrete DA, the team witnessed that gonads were no longer affected by caloric restriction. Neither was life expectancy. If DA was provided externally, both responses reappeared. Even more interestingly, if the gonads were put to sleep artificially, DA was no longer necessary to increase survival. “This proves that both responses are dependent; we think that when gonads are silenced, they send a message to all the mechanisms involved in survival,” says Aguilaniu. The team is now studying the nature of this signal, in the hope of finding a way of reproducing it artificially, and improving longevity without starvation and fertility loss. ii michel.dhome@univ-bpclermont.fr 1. Institut Pascal (CNRS / Université Blaise-Pascal / IFMA). 1. M. Thondamal et al, “Steroid hormone signaling links reproduction to lifespan in dietary-restricted C. elegans,” Nat Commun., 2014. 5(9): 4879. 2. Laboratoire de biologie moléculaire de la cellule (CNRS / ENS de Lyon). Transportation Driver not Needed BY ARBY GHARIBIAN hugo.aguilaniu@ens-lyon.fr © MANJUNATHA THONDAMAL © EASYMILE


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