The Polypedilum vanderplanki is more commonly known just as a midge, a particularly small form of common fly. Midges are found all over the world in absolutely every climate and ecosystem, but this one hails from northern Nigeria where the dry season can last upwards of eight months in a year. Given that midges depend on standing water to breed and develop, this might seem a problem.The Polypedilum vanderplanki, known also as the sleeping chironomid, is no ordinary fly, however, and has adapted to its homeland such that it's capable of effectively turning into insect jerky. The sleeping chironomid is able to lose 97 percent of its body water and still survive, re-hydrate, and buzz another day.For the first time, researchers have decoded the portion of the Nigerian midge's genome responsible for its extreme resilience. Their open-access report is published in the current edition of Nature Communications. The Polypedilum vanderplanki's resilience suggests this is one such organism capable of surviving the extreme environmental rigors of space.In addition to extreme dryness, the Nigerian midge can handle extreme temperature variations, from 90°C to -270°C, as well as vacuum conditions and intense blasts of radiation. These midges can last in their dried-out forms (known as anhydrobiosis) for up to 17 years. Rejuvenation can take as little as one hour.These abilities of the sleeping chironomid are unique among insects and are typically the domain of microscopic organisms (such as tardigrades). As such, the mechanisms behind the midge's survival abilities are unique and complex, the result of a unique "gene island" not found in any related midge (or insect) species. These abilities may also be portable to other organisms.
The researchers behind the current study—an international team with members from Russia, the United States, and Japan— suggest that it might be possible to port these capabilities to otherwise fragile cargo blood samples and fertilized human eggs, which could then be stored without refrigeration.The sleeping chironomid's survival mechanisms are indeed varied. They can be traced to a array of protective biomolecules, "including late embryogenesis abundant (LEA) proteins, trehalose, antioxidants, and heat–shock proteins," in the study's words.Much of the Nigerian midge's defenses have to do with the protective effects of trehalose, a sugar, and proteins generated to act as molecular shields. But that's not the whole story. A 2010 study found that, in the midge was able to repair extreme DNA damage, whether from dehydration or radiation, within 96 hours. This ability to piece together fragmented genetic material is more often seen in plant seeds and bacteria, not in macroscopic organisms.The possibility of storing blood and eggs with midge DNA is neat and all, but it's worth taking a step back to appreciate that these shrewd adaptations exist at all. It's evidence for what's possible when life is threatened by the most extreme conditions. In a way, that's better hope for extraterrestrial life than any exoplanet discovery.
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