剑桥雅思14阅读Test4Passage1原文翻译

这篇文章讨论了一种被称为菲德勒牙齿蚁的蚂蚁，它表现出抗衰老的特性。研究者发现，这种蚂蚁的工蚁在年龄增长过程中没有明显的衰退迹象，它们的大脑依然敏锐，并能执行各种任务，比如照顾幼崽和追踪气味。研究还发现，这些老年蚂蚁的大脑细胞没有接近死亡的迹象，血清素和多巴胺水平也没有下降。这些发现对于理解衰老过程以及开展衰老相关研究具有重要意义。虽然这些发现是针对菲德勒牙齿蚁进行的，但对于其他社会昆虫物种及更大动物的衰老科学也可能提供线索。总的来说，这篇文章的主旨是介绍菲德勒牙齿蚁表现出的抗衰老特性，以及这些发现对理解衰老过程的重要性。

第1段

Pheidole dentata, a native ant of the south-eastern U.S., isn’t immortal. But scientists have found that it doesn’t seem to show any signs of aging. Old worker ants can do everything just as well as the youngsters, and their brains appear just as sharp. ‘We get a picture that these ants really don’t decline,’ says Ysabel Giraldo, who studied the ants for her doctoral thesis at Boston University.

菲德勒牙齿蚁是美国东南部的一种本土蚂蚁，它并不不朽。但科学家们发现，它似乎没有显示任何衰老的迹象。老工蚁可以像年轻人一样做任何事情，它们的大脑看起来同样敏锐。波士顿大学的博士论文研究了这些蚂蚁的伊莎贝尔·吉拉尔多说：“我们得到的印象是这些蚂蚁真的没有衰老。”

第2段

Such age-defying feats are rare in the animal kingdom. Naked mole rats can live for almost 30 years and stay fit for nearly their entire lives. They can still reproduce even when old, and they never get cancer. But the vast majority of animals deteriorate with age just like people do. Like the naked mole rat, ants are social creatures that usually live in highly organised colonies. ‘It’s this social complexity that makes P. dentata useful for studying aging in people,’ says Giraldo, now at the California Institute of Technology. Humans are also highly social, a trait that has been connected to healthier aging. By contrast, most animal studies of aging use mice, worms or fruit flies, which all lead much more isolated lives.

这种抗衰老的特性在动物界十分罕见。裸鼠鼹鼠可以活近30年并且几乎一生健康。它们即使年老也能繁殖，并且从不患癌症。但绝大多数动物都会像人一样随着年龄的增长而恶化。与裸鼠鼹鼠一样，蚂蚁是通常生活在高度有组织的社群中的社交动物。“这种社会复杂性使P. dentata成为研究人类衰老的有用对象，”现在在加利福尼亚理工学院的吉拉尔多说。人类也是高度社交的，这一特征与更健康的衰老有关。相比之下，大多数动物的衰老研究使用的是老鼠、蠕虫或果蝇，它们的生活更加孤立。

第3段

In the lab, P. dentata worker ants typically live for around 140 days. Giraldo focused on ants at four age ranges: 20 to 22 days, 45 to 47 days, 95 to 97 days and 120 to 122 days. Unlike all previous studies, which only estimated how old the ants were, her work tracked the ants from the time the pupae became adults, so she knew their exact ages. Then she put them through a range of tests.

在实验室中，P. dentata工蚁通常寿命约为140天。吉拉尔多四个年龄段的蚂蚁：20至22天，45至47天，95至97天和120至122天。与以往只是估计蚂蚁年龄的研究不同，她的工作从蛹成为成年蚁的时间开始追踪蚂蚁，因此她知道它们的确切年龄。然后她对它们进行了一系列测试。

第4段

Giraldo watched how well the ants took care of the young of the colony, recording how often each ant attended to, carried and fed them. She compared how well 20-day-old and 95-day-old ants followed the telltale scent that the insects usually leave to mark a trail to food. She tested how ants responded to light and also measured how active they were by counting how often ants in a small dish walked across a line. And she experimented with how ants react to live prey: a tethered fruit fly. Giraldo expected the older ants to perform poorly in all these tasks. But the elderly insects were all good caretakers and trail-followers—the 95-day-old ants could track the scent even longer than their younger counterparts. They all responded to light well, and the older ants were more active. And when it came to reacting to prey, the older ants attacked the poor fruit fly just as aggressively as the young ones did, flaring their mandibles or pulling at the fly’s legs.

吉拉尔多观察了蚂蚁对整个社群的幼崽照料的能力，记录了每只蚂蚁照料、携带和喂食幼崽的频率。她比较了20天和95天的蚂蚁对昆虫通常留下的特殊气味追踪食物的情况。她测试了蚂蚁对光的反应，并通过计算在小碟中的蚂蚁跨过线的频率来测量它们的活跃度。她还实验了蚂蚁对活捕猎物的反应：被拴住的果蝇。吉拉尔多预计老蚂蚁在所有这些任务中表现不佳。但老年蚂蚁都是优秀的照顾者和追踪者-95天的蚂蚁甚至比它们年轻的同伴追踪气味的时间更长。它们对光的反应都很好，老蚂蚁更活跃。在对捕食对象的反应方面，老蚂蚁和年轻蚂蚁一样积极地攻击可怜的果蝇，张开大颚或拉扯果蝇的腿。

第5段

Then Giraldo compared the brains of 20-day-old and 95-day-old ants, identifying any cells that were close to death. She saw no major differences with age, nor was there any difference in the location of the dying cells, showing that age didn’t seem to affect specific brain functions. Ants and other insects have structures in their brains called mushroom bodies, which are important for processing information, learning and memory. She also wanted to see if aging affects the density of synaptic complexes within these structures—regions where neurons come together. Again, the answer was no. What was more, the old ants didn’t experience any drop in the levels of either serotonin or dopamine—brain chemicals whose decline often coincides with aging. In humans, for example, a decrease in serotonin has been linked to Alzheimer’s disease.

然后吉拉尔多比较了20天和95天的蚂蚁的大脑，识别出接近死亡的细胞。她发现年龄上没有明显差异，也没有死亡细胞的位置差异，表明年龄似乎不会影响特定的大脑功能。蚂蚁和其他昆虫大脑中有一个叫做蘑菇体的结构，对处理信息、学习和记忆都很重要。她还想看看年龄是否影响这些结构内突触复合物的密度-神经元聚集的区域。同样，答案是否定的。更重要的是，老蚂蚁的血清素和多巴胺水平都没有下降-这两种脑化学物质的下降通常与衰老有关。例如，人类的血清素减少与阿尔茨海默病有关。

第6段

‘This is the first time anyone has looked at both behavioral and neural changes in these ants so thoroughly,’ says Giraldo, who recently published the findings in the Proceedings of the Royal Society B. Scientists have looked at some similar aspects in bees, but the results of recent bee studies were mixed—some studies showed age-related declines, which biologists call senescence, and others didn’t. ‘For now, the study raises more questions than it answers,’ Giraldo says, ‘including how P. dentata stays in such good shape.’

吉拉尔多最近在《皇家学会报告》上发表了这些发现，她说：“这是有史以来第一次如此彻底地研究这些蚂蚁的行为和神经变化。”科学家们在蜜蜂的一些类似方面进行了研究，但最近的蜜蜂研究结果不一-一些研究表明年龄相关的衰退，生物学家称之为衰老，而另一些则没有。“目前，这项研究引发了更多的问题，而非答案，”吉拉尔多说，“包括P. dentata如何保持如此良好的状态。”

第7段

Also, if the ants don’t deteriorate with age, why do they die at all? Out in the wild, the ants probably don’t live for a full 140 days thanks to predators, disease and just being in an environment that’s much harsher than the comforts of the lab. ‘The lucky ants that do live into old age may suffer a steep decline just before dying,’ Giraldo says, but she can’t say for sure because her study wasn’t designed to follow an ant’s final moments.

 此外，如果蚂蚁不会随着年龄的增长而恶化，那么它们为什么会死呢？在野外，蚂蚁可能不会活满140天，这要归功于捕食者、疾病以及在远比实验室舒适的环境中生活。吉拉尔多说：“那些幸运活到老年的蚂可能在临死之前会经历急剧的衰退，”但她无法确定，因为她的研究并没有设计跟踪蚂蚁的最后时刻。

第8段

‘It will be important to extend these findings to other species of social insects,’ says Gene E. Robinson, an entomologist at the University of Illinois at Urbana-Champaign. This ant might be unique, or it might represent a broader pattern among other social bugs with possible clues to the science of aging in larger animals. Either way, it seems that for these ants, age really doesn’t matter.

“将这些发现扩展到其他社会昆虫物种将是重要的，”伊利诺伊大学厄巴纳-香槟分校的昆虫学家吉恩·罗宾逊说。这种蚂蚁可能是独一无二的，或者它可能代表其他社交虫类中更广泛的模式，可能为更大动物的衰老科学提供线索。不管怎样，对于这些蚂蚁来说，年龄似乎真的不重要。