美国国家公共电台 NPR--The astonishing vanishing act of the glassfrog, revealed

The astonishing vanishing act of the glassfrog, revealed

Transcript¹

Jesse Delia says it happened in Panama. A few years back, he was finishing up his field work — a research project examining the parental² behavior of a type of glassfrog. He brought a handful of these transparent³, half dollar-sized frogs to the lab for a photo shoot.

It led to an exciting discovery.

"I wanted to get some photos of a pretty glassfrog belly⁴," Delia tells NPR. He placed them in a Petri dish and saw each frog's circulatory system through its translucent⁵ skin — "red with red blood cells."

But when he came back later, the frogs were sleeping and the blood "was gone."

It was as if the arteries⁶ and veins⁷ had just melted away. "I thought it was crazy," recalls Delia, now a biologist at the American Museum of Natural History in New York.

He took a video of the glassfrog's pumping heart and sent it to his longtime collaborator⁸, Carlos Taboada, a biologist at Duke University.

"It was colorless," Taboada says. Not even the telltale red streak⁹ of a vessel¹⁰ in the frog's belly was visible. "It was insane. I had never seen anything like that."

Both Delia and Taboada wanted to know — where'd all the frogs' red blood go?

In a new paper in the journal Science, Taboada, Delia and their collaborators offer an answer: "They hide most of their red blood cells in their liver," Delia explains.

During the day, while the glassfrogs are asleep on green leaves, they're vulnerable to predators¹¹, so they achieve camouflage¹² by becoming super transparent. (Their livers, among other organs, are coated in highly reflective white crystals.) Since their red blood cells are transporting very little oxygen, Delia says the frogs likely have "some alternative process that allows them to keep their cells alive during transparency." Then, at night, when the frogs become active, "feeding and mating, going about their regular business," the vitreous amphibians¹³ release their red blood cells back into circulation.

Taboada says the frogs "pack roughly 90% of their red blood cells in a really, really small volume. Normally, those conditions can trigger some clotting¹⁴ disorders¹⁵." The researchers say that knowing how the glassfrogs avoid a blood clotting cascade¹⁶ could pave the way for new anticoagulants for humans.

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 parental   

adj.父母的；父的；母的

参考例句：

• He encourages parental involvement in the running of school.他鼓励学生家长参与学校的管理。
• Children always revolt against parental disciplines.孩子们总是反抗父母的管束。

3 transparent   

adj.明显的，无疑的；透明的

参考例句：

• The water is so transparent that we can see the fishes swimming.水清澈透明，可以看到鱼儿游来游去。
• The window glass is transparent.窗玻璃是透明的。

4 belly   

n.肚子，腹部；(像肚子一样)鼓起的部分，膛

参考例句：

• The boss has a large belly.老板大腹便便。
• His eyes are bigger than his belly.他眼馋肚饱。

5 translucent   

adj.半透明的；透明的

参考例句：

• The building is roofed entirely with translucent corrugated plastic.这座建筑完全用半透明瓦楞塑料封顶。
• A small difference between them will render the composite translucent.微小的差别,也会使复合材料变成半透明。

6 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

7 veins   

n.纹理；矿脉( vein的名词复数 )；静脉；叶脉；纹理

参考例句：

• The blood flows from the capillaries back into the veins. 血从毛细血管流回静脉。 来自《简明英汉词典》
• I felt a pleasant glow in all my veins from the wine. 喝过酒后我浑身的血都热烘烘的，感到很舒服。 来自《简明英汉词典》

8 collaborator   

n.合作者，协作者

参考例句：

• I need a collaborator to help me. 我需要个人跟我合作，帮我的忙。
• His collaborator, Hooke, was of a different opinion. 他的合作者霍克持有不同的看法。

9 streak   

n.条理，斑纹，倾向，少许，痕迹；v.加条纹，变成条纹，奔驰，快速移动

参考例句：

• The Indians used to streak their faces with paint.印第安人过去常用颜料在脸上涂条纹。
• Why did you streak the tree?你为什么在树上刻条纹？

10 vessel   

n.船舶；容器，器皿；管，导管，血管

参考例句：

• The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
• You should put the water into a vessel.你应该把水装入容器中。

11 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

12 camouflage   

n./v.掩饰，伪装

参考例句：

• The white fur of the polar bear is a natural camouflage.北极熊身上的白色的浓密软毛是一种天然的伪装。
• The animal's markings provide effective camouflage.这种动物身上的斑纹是很有效的伪装。

13 amphibians   

两栖动物( amphibian的名词复数 )； 水陆两用车； 水旱两生植物； 水陆两用飞行器

参考例句：

• The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
• Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。

14 clotting   

v.凝固( clot的现在分词 )；烧结

参考例句：

• The study was also based only on the one anti-clotting drug. 所用抗血栓药物也仅限于一种。 来自互联网
• A plasma protein that is converted into thrombin during blood clotting. 凝血原酶一种血浆蛋白质，在血液凝聚时转化成凝血''。'酵'。''''。'素'。''。 来自互联网

15 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

16 cascade   

n.小瀑布，喷流；层叠；vi.成瀑布落下

参考例句：

• She watched the magnificent waterfall cascade down the mountainside.她看着壮观的瀑布从山坡上倾泻而下。
• Her hair fell over her shoulders in a cascade of curls.她的卷发像瀑布一样垂在肩上。