墨尔本PTE素材库—high sugar diet makes flies drop like flies

high sugar diet makes flies drop like flies

中文批注

这篇文章讲述的是关于高糖分的食物与果蝇的生命之间的关系。这个话题是不是很奇妙很新颖呢？小编第一次看到的时候也觉得眼前一亮，非常想要好好研读一下呢！

对于人类而言，有一种叫做leptin的激素会提醒我们已经吃饱了，那么对于果蝇来说呢？有没有一种相似的荷尔蒙呢？答案是有的。如果把这种相关的基因给消除，那么这些昆虫就会继续吃，不停的吃。科学家们之所以会把时间与精力花在研究这个问题上，是因为他们觉得这样也可以慢慢的研究出与人类有关的问题。至于这些问题的答案，就留待大家听录音或者做阅读理解了哦！小编在此就卖个关子，不透露啦！

澳大利亚语言学院(AIL)会定期给大家整理一些英语学习的资料，大家可以每天或者隔天，花一小时左右的时间来听这些录音，或者看这些文章，从而渐进的提升自己的英语基本功！

[Key Vocabulary]

Obese: adj. 肥胖的，过胖的

Overeat: Vt. 吃过量

Silly: adj. 愚蠢的，不明事理的，没头脑的

Cabinet: n. 内阁，橱柜

Hormone: [生理] 激素，荷尔蒙

Leptin: 瘦素，瘦蛋白

Molecular: adj. [化学] 分子的，由分子组成的

Gene: [遗] 基因，遗传因子

Encode: Vt. 译成密码，编码

Equivalent: adj. 等价的，相同的; n. 等价物，相等物

Metabolism: n. [生理] 新陈代谢

Tubby: adj. 桶状的，肥胖的

Eliminate: Vt. 消除，排除

Binge: n. 狂欢，狂闹；Vt. 放纵；Vi. 大吃大喝

Bender: n. 饮酒作乐

Sucrose: n. [食品] [有化] 蔗糖

Trigger: Vt. 引发，引起，触发

Accelerate: V. 加速

Full Transcript

A study examines the effects of a high-sugar diet on the life spans of fruit flies. Another studies how the flies’ appetite-suppressing pathways may be similar to ours. Karen Hopkin reports. 

I don’t believe, in all my years, I have ever seen a fruit fly I would consider obese. But, thanks to the wonders of modern science, that’s all about to change. Because a team of researchers from Cold Spring Harbor laboratory has produced the first flies that are genetically engineered to overeat.

If you are wondering…why…it’s not as silly as it might sound. A big part of weight control has to do with making healthy dietary choices and knowing when to step away from the snack cabinet. But what controls those behaviours?

Well, we humans have a hormone called leptin that tells us that we’re full. After eating, leptin is released from our fat cells. And it travels to our brains to signal that we’ve had enough. Indeed, people who don’t produce leptin…or who lack the molecular machinery to detect it…really pack on the pounds.

In the new study, researchers discovered a hormone that acts the same way in flies. And when they deleted the gene that encodes it, the hormonally deficient insects just kept eating. And when presented with the fly equivalent of a high-fat or high-sugar diet, they gained three times more weight than did their hormonally competent peers. The findings appear in the journal Cell Metabolism. [Jennifer Beshel et al., A Leptin Analog Locally Produced in the Brain Acts via a Conserved Neural Circuit to Modulate Obesity-Linked Behaviors in Drosophila]

Interestingly, giving human leptin to these tubby bugs eliminates their tendency to binge. That suggests that by studying these flies, scientists might learn something that’s relevant to us.

In the meantime, researchers from the U.K. and Australia have also been plying flies with sweet treats. And they found that consuming large amounts of sugar may lead to fewer birthday cakes.

In this study, researchers compared the life spans of flies that ate a healthy diet, with 5 percent sugar…to those that went on a three-week bender of 40 percent sucrose. That’s the equivalent, the researchers note, of a person who really took Marie Antoinette’s advice to heart and ate only cake for two decades.

The results? The sugar-fed flies lost about 7 percent of their already brief 90-day life span. And that was even if they reverted to the healthy diet after their three weeks on sweets. These results appear in the journal Cell Reports. [Adam J. Dobson et al, Nutritional Programming of Lifespan by FOXO Inhibition on Sugar-Rich Diets]

The sugar overload apparently triggered long-term changes in gene activity…which accelerated aging and had the sugar-buzzed flies dropping like, well, like flies.

The findings suggest that you can have your cake and eat it, too. But not for long.

—Karen Hopkin

(Source: https://www.scientificamerican.com/podcast/episode/high-sugar-diet-makes-flies-drop-like-flies/)