Extending lifespan Thanks, Mum!

　　延長壽命 謝啦，老媽!

　　An obscure group of animals may reveal the secret of elongating life

　　一群不為人知的動物可能會揭開長壽之謎

　　THE one sure way to prolong an animal s life is, paradoxically, to starve it. Caloricrestriction , as it is known in the trade, works for everything from threadworms tomammals . So it is no surprise that it also works for a group of small creatures known asrotifers. If that were the only result of Shugo Watabe s experiments on the critters, at theUniversity of Tokyo, it would scarcely be worth reporting. What makes this news is that theoffspring of the rotifers in question also lived longer than normal. And thatthe inheritanceof an acquired characteristicis quite startling.

　　矛盾的是，延長動物壽命的方法，竟然是使其挨餓?？茖W界的同行都知道，有名的 熱量限制 法則對小至線蟲，大至哺乳動物的動物界都適用。所以當該條法則運用到一群名叫輪蟲的生物上也就不足為奇了。如果東京大學的修吾渡部的輪蟲實驗僅是如此的話，也就沒有報道的價值了。具有資訊價值的是，上述輪蟲后代的生命也比普通輪蟲要長。那后天的從父輩繼承下的特質實在很令人吃驚。

　　Rotifers are unusual in that they often reproduce by parthenogenesis . A parthenogenetic population is, by definition,all female and the result, give or take the odd mutation, is that a rotifer s daughters aregenetically identical to her. That makes rotifers convenient subjects for studies of thecontroversial idea that characteristics acquired during an individual s life can be passeddown the generations in ways that are independent of mutations in the DNA.

　　輪蟲并不普通，因為他們的繁殖方式是孤雌生殖。顧名思義，孤雌生殖群體全是雌性;如果沒有接受和傳遞罕見基因突變，那么輪蟲的雌性后代與母體是完全相同的。這使得輪蟲成為十分方便的研究對象：人們對在個體生命期中，后天習得的特征與繁殖后代中的DNA突變并不相關這個觀點存在爭議。

　　Dr Watabe and his colleagues first looked at whether caloric restriction does, indeed, workits magic on rotifers. It does. Without it, as they report in Functional Ecology, their animalslived for an average of 8.8 days. With it they lived for 13.5 days. The intriguing result camewhen they did the same thing with the rotifers offspring. The daughters of those rotiferswhich had been fed as much as they could eat lived for 9.5 days if treated likewise and 14.4 if put on short commons. Those born ofcalorie-restricted mothers lived for 12.7 and 16.8 days respectively. Something, then, isbeing passed on that is having an effect down the generations.

　　渡邊博士和他的同事第一次研究熱量限制的機制是否對輪蟲同樣有效。確實有效。他們在《機能生態學》雜志上報道說，沒有了熱量限制，輪蟲的平均生命期為13.5天。當它們對輪蟲的后代采取了同樣的熱量限制后，得到了有趣的結果。輪蟲的母系如果得到了飽和的食物量，它們那些也同樣飽食的后代可以存活了9.5天，如果后代食物量減少，則可以活14.4天。那些誕生于熱量限制的母系后代則在飽食和不飽食的情況下分別存活了12.7 和16.8天。那么，一定有某種物質通過上下代傳遞，對個體生命產生了影響。

　　That something seems to be related to an enzyme called catalase. This enzyme degradeshydrogen peroxide, a highly reactive chemical that creates cellular damage of the sortassociated with ageing. Dr Watabe found that the offspring of calorie-restricted mothershave more catalase than those of mothers who were fed without restriction.

　　這種物質似乎與一種名叫過氧化氫酶的酶有關。這種酶分解過氧化氫這種反映活性很高、可以在細胞老化過程中損害細胞的物質。渡邊博士發現這種經過熱量限制的母體的后代，其過氧化氫酶含量比沒有食量限制的母體后代更多。

　　The researchers also detected higher levels of the enzyme in the eggs of calorie-restrictedmothers, so it could be that their offspring are simply endowed with the stuff. A moreintriguing possibility, though, is that the relevant genes are affected by epigenesis, aprocess in which chemicals attached to the DNA control its activity. Epigenetic modificationsare often retained when cells divide, and can sometimes be passed on to offspring.

　　研究人員同時檢測了得到熱量控制的母體產下的卵，它的過氧化氫酶濃度較高，所以這可能是這些后代與生俱來的。然而，一個更有意思的可能性是后生作用影響了這些基因。后生作用是指與DNA相接的化學物質來控制其活動。細胞分裂期往往阻礙表觀遺傳修飾，并且會把這種機制傳遞給下一代。

　　If inherited epigenetic changes were causing daughter rotifers to produce more catalase, itwould raise the question of whether a similar thing happens in other species and, if so,whether it might be induced artificially, without all the tedious business of a lifetime sstarvation. That would certainly be worth looking at. The search for an elixir of life has takenpeople to some strange places. Few, though, are stranger than rotifers.

　　如果母系輪蟲后代從母體繼承了后生變化，產生了更多的過氧化氫酶，人們同樣也會考慮相似的事情會不會也發生在其他物種上;而且，如果同樣發生，可否通過人工誘導的方法，而不是通過冗長到一輩子都餓著肚子。長生不老的研究已經將人類指向了一些奇怪的領域。而沒有幾個比輪蟲更奇怪的了。

　　Extending lifespan Thanks, Mum!

　　延長壽命 謝啦，老媽!

　　An obscure group of animals may reveal the secret of elongating life

　　一群不為人知的動物可能會揭開長壽之謎

　　THE one sure way to prolong an animal s life is, paradoxically, to starve it. Caloricrestriction , as it is known in the trade, works for everything from threadworms tomammals . So it is no surprise that it also works for a group of small creatures known asrotifers. If that were the only result of Shugo Watabe s experiments on the critters, at theUniversity of Tokyo, it would scarcely be worth reporting. What makes this news is that theoffspring of the rotifers in question also lived longer than normal. And thatthe inheritanceof an acquired characteristicis quite startling.

　　矛盾的是，延長動物壽命的方法，竟然是使其挨餓?？茖W界的同行都知道，有名的 熱量限制 法則對小至線蟲，大至哺乳動物的動物界都適用。所以當該條法則運用到一群名叫輪蟲的生物上也就不足為奇了。如果東京大學的修吾渡部的輪蟲實驗僅是如此的話，也就沒有報道的價值了。具有資訊價值的是，上述輪蟲后代的生命也比普通輪蟲要長。那后天的從父輩繼承下的特質實在很令人吃驚。

　　Rotifers are unusual in that they often reproduce by parthenogenesis . A parthenogenetic population is, by definition,all female and the result, give or take the odd mutation, is that a rotifer s daughters aregenetically identical to her. That makes rotifers convenient subjects for studies of thecontroversial idea that characteristics acquired during an individual s life can be passeddown the generations in ways that are independent of mutations in the DNA.

　　輪蟲并不普通，因為他們的繁殖方式是孤雌生殖。顧名思義，孤雌生殖群體全是雌性;如果沒有接受和傳遞罕見基因突變，那么輪蟲的雌性后代與母體是完全相同的。這使得輪蟲成為十分方便的研究對象：人們對在個體生命期中，后天習得的特征與繁殖后代中的DNA突變并不相關這個觀點存在爭議。

　　Dr Watabe and his colleagues first looked at whether caloric restriction does, indeed, workits magic on rotifers. It does. Without it, as they report in Functional Ecology, their animalslived for an average of 8.8 days. With it they lived for 13.5 days. The intriguing result camewhen they did the same thing with the rotifers offspring. The daughters of those rotiferswhich had been fed as much as they could eat lived for 9.5 days if treated likewise and 14.4 if put on short commons. Those born ofcalorie-restricted mothers lived for 12.7 and 16.8 days respectively. Something, then, isbeing passed on that is having an effect down the generations.

　　渡邊博士和他的同事第一次研究熱量限制的機制是否對輪蟲同樣有效。確實有效。他們在《機能生態學》雜志上報道說，沒有了熱量限制，輪蟲的平均生命期為13.5天。當它們對輪蟲的后代采取了同樣的熱量限制后，得到了有趣的結果。輪蟲的母系如果得到了飽和的食物量，它們那些也同樣飽食的后代可以存活了9.5天，如果后代食物量減少，則可以活14.4天。那些誕生于熱量限制的母系后代則在飽食和不飽食的情況下分別存活了12.7 和16.8天。那么，一定有某種物質通過上下代傳遞，對個體生命產生了影響。

　　That something seems to be related to an enzyme called catalase. This enzyme degradeshydrogen peroxide, a highly reactive chemical that creates cellular damage of the sortassociated with ageing. Dr Watabe found that the offspring of calorie-restricted mothershave more catalase than those of mothers who were fed without restriction.

　　這種物質似乎與一種名叫過氧化氫酶的酶有關。這種酶分解過氧化氫這種反映活性很高、可以在細胞老化過程中損害細胞的物質。渡邊博士發現這種經過熱量限制的母體的后代，其過氧化氫酶含量比沒有食量限制的母體后代更多。

　　The researchers also detected higher levels of the enzyme in the eggs of calorie-restrictedmothers, so it could be that their offspring are simply endowed with the stuff. A moreintriguing possibility, though, is that the relevant genes are affected by epigenesis, aprocess in which chemicals attached to the DNA control its activity. Epigenetic modificationsare often retained when cells divide, and can sometimes be passed on to offspring.

　　研究人員同時檢測了得到熱量控制的母體產下的卵，它的過氧化氫酶濃度較高，所以這可能是這些后代與生俱來的。然而，一個更有意思的可能性是后生作用影響了這些基因。后生作用是指與DNA相接的化學物質來控制其活動。細胞分裂期往往阻礙表觀遺傳修飾，并且會把這種機制傳遞給下一代。

　　If inherited epigenetic changes were causing daughter rotifers to produce more catalase, itwould raise the question of whether a similar thing happens in other species and, if so,whether it might be induced artificially, without all the tedious business of a lifetime sstarvation. That would certainly be worth looking at. The search for an elixir of life has takenpeople to some strange places. Few, though, are stranger than rotifers.

　　如果母系輪蟲后代從母體繼承了后生變化，產生了更多的過氧化氫酶，人們同樣也會考慮相似的事情會不會也發生在其他物種上;而且，如果同樣發生，可否通過人工誘導的方法，而不是通過冗長到一輩子都餓著肚子。長生不老的研究已經將人類指向了一些奇怪的領域。而沒有幾個比輪蟲更奇怪的了。