Worms sTOP ageing when they are starved of food and can go onto live twice as long as normal, a new study has shown.
一项新研究发现，蠕虫在缺少食物的状况下会停止老化并能存活正常状况下两倍的时间。Researchers found that nematode（线虫） worms entered a state of arrested development（发育停滞） when food was taken away from them.They continued to move and forage1 but their cells and organs were suspended in an ageless, inactive state.once the worms had access to food again, they began to grow normally and doubled their lifespan.Scientists from Duke University, North Carolina, US reported their findings in the journal PLOS Genetics.Organisms including flies, yeast3, monkeys and worms have previously4 been put on diets and shown to have their life spans extended by 30 to 200%, compared with those able to eat normally.But how it happens remains5 unclear.The research team set out to determine how growing tissues respond to starvation.Tiny nematode worms - Caenorhabditis elegans - which are normally found underground, were chosen because they reach adulthood6 in three to four days and develop in similar ways to each other.They are also translucent7 and composed of only a few hundred cells, making changes in development easy to see under a microscope.In the wild, the worms can experience bouts8（来回一次） of feast or famine（饥荒） that are likely to affect their development and lifespan.The authors allowed the worms to grow to a specific developmental stage, just before the start of rapid cell growth.Food was then removed from the worms and their reactions observed.Within hours the worms development sTOPped. once the worms could feed again, their development resumed and they grew into normal adults.The authors found that worms development was not continuous but sTOPped at two main stages, which they called checkpoints.They explained that a worm needs enough nutrients9 to pass through to the next developmental stages. If it is deprived of nutrients it has to wait until it has built them back up before its development can continue.Organisms have to monitor their environment and decide whether or not it is amenable10（有责任的） to their development, lead author, Adam Schindler said.If it isnt, they sTOP. If it is, they go. Those checkpoints seem to exist to allow the animal to make that decision. And the decision has implications, because the resources either go to development or to survival.The study found the worms could be starved for at least two weeks and still develop normally once they were fed.The period of arrested development allowed the worm to double its normal two-week lifespan.Mr Schindler said: From an evolutionary11 perspective this finding highlights the importance of an effective response to starvation for optimal12 fitness of the organism.The team say their work may have implications for human ageing and also cancer biology, especially as the behaviour discovered in worms is similar to tumours14 lying dormant15（休眠的） for years before growing again.They are now performing genetic2 studies to see if they can find another way to force worms to pause their development.The main question is how the decision is made to either arrest development or continue, Mr Schindler said.Understanding the key players in this decision could provide insights into why tissues degenerate16 during ageing and reveal possible ways of slowing this degeneration.
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1 forage n.饲料，粮草；v.搜寻，翻寻 参考例句： They were forced to forage for clothing and fuel.他们不能不去探寻衣服和燃料。 Now the nutritive value of the forage is reduced.此时牧草的营养成分也降低了。
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