科学美国人60秒 SSS 2014-07-31_在线英语听力室

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Pack rat. The name is synonymous with hoarding¹. And researchers have learned that pack rats can actually increase the range of foods they’re able to eat because of their collection of gut² bacteria.

Pack rats live in the American Southwest, where they nosh on the native vegetation. Some of these plants produce protective toxins³, for example the junipers in the Great Basin desert or the creosote bushes of the Mojave. But pack rats seem to eat these noxious⁴ shrubs⁵ with impunity⁶.

The researchers found that pack rats from the Mojave harbor gut bacteria that can break down creosote. When antibiotics⁷ depleted⁸ the pack rats’ gut bacteria, the animals suddenly found creosote nearly indigestible.

Further, the researchers found that they could take pack rats from the Great Basin—the ones that eat juniper—and give them the ability to eat creosote. All they needed was a fecal transplant, which supplied the necessary gut bacteria from their Mojave-based neighbors. The work appears in the journal Ecology Letters. [Kevin D. Kohl et al., Gut microbes of mammalian herbivores facilitate intake⁹ of plant toxins]

The findings show the importance of gut bacteria for eating some otherwise dicey foods. They could also allow farmers to expand the diet of their livestock¹⁰. Cows with the right gut bacteria could feast on what was formerly¹¹ feh.

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1 hoarding
n.贮藏；积蓄；临时围墙；囤积v.积蓄并储藏（某物）( hoard的现在分词 )
参考例句：
After the war, they were shot for hoarding. 战后他们因囤积而被枪决。来自《简明英汉词典》 Actually he had two unused ones which he was hoarding up. 其实他还藏了两片没有用呢。来自英汉文学

2 gut
n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏
参考例句：
It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。 My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

3 toxins
n.毒素( toxin的名词复数 )
参考例句：
The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。 Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。来自《简明英汉词典》

4 noxious
adj.有害的，有毒的；使道德败坏的，讨厌的
参考例句：
Heavy industry pollutes our rivers with noxious chemicals.重工业产生的有毒化学品会污染我们的河流。 Many household products give off noxious fumes.很多家用产品散发有害气体。

5 shrubs
灌木( shrub的名词复数 )
参考例句：
The gardener spent a complete morning in trimming those two shrubs. 园丁花了整个上午的时间修剪那两处灌木林。 These shrubs will need more light to produce flowering shoots. 这些灌木需要更多的光照才能抽出开花的新枝。

6 impunity
n.(惩罚、损失、伤害等的)免除
参考例句：
You will not escape with impunity.你不可能逃脱惩罚。 The impunity what compulsory insurance sets does not include escapement.交强险规定的免责范围不包括逃逸。

7 antibiotics
n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )
参考例句：
the discovery of antibiotics in the 20th century 20世纪抗生素的发现 The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

8 depleted
adj. 枯竭的, 废弃的动词deplete的过去式和过去分词
参考例句：
Food supplies were severely depleted. 食物供应已严重不足。 Both teams were severely depleted by injuries. 两个队都因队员受伤而实力大减。

9 intake
n.吸入，纳入；进气口，入口
参考例句：
Reduce your salt intake.减少盐的摄入量。 There was a horrified intake of breath from every child.所有的孩子都害怕地倒抽了一口凉气。

10 livestock
n.家畜，牲畜
参考例句：
Both men and livestock are flourishing.人畜两旺。 The heavy rains and flooding killed scores of livestock.暴雨和大水淹死了许多牲口。

11 formerly
adv.从前，以前
参考例句：
We now enjoy these comforts of which formerly we had only heard.我们现在享受到了过去只是听说过的那些舒适条件。 This boat was formerly used on the rivers of China.这船从前航行在中国内河里。

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科学美国人60秒 SSS 2014-07-31