英语听力:自然百科 马蹄蟹与人类(一)
时间:2018-12-26 作者:英语课 分类:自然百科2009年
As the water is warm and tides grow high, horseshoe crabs 2 leave the ocean floor and make their way to the shores and estuaries 3 of the Atlantic Coast. Here in the sheltered waters of South Carolina, they suddenly emerge by the thousands in the spawning 5 ritual they've performed for hundreds of millions of years. On the highest tides, they drag themselves to shore to lay their eggs. Crabs don't mature till they are nine or ten. By then, they've molted 6 for the last time and their permanent shells can host an ecosystem 7 of hitchhikers. Horseshoe crabs are safest on the ocean floor, but the only way to carry on the species is to take a risk.
We see the ones that see us come and turn and take off to the water. We caught him before he knows us. You know.
Jerry Golt and his father Bob have worked these waters for decades.
We work the moons. The horseshoe crabs come up and spawn 4 on the moons in the springtime.
If you actually get into the water, you can feel them swimming and sometimes you can't even catch them because they'll get to swimming so fast. A lot of people seem to be scared when they first see them on the beaches. They do look a little scary but what I do is put them right up against my face and as you can see they do not hurt. Their pinchers are all very light. These are harmless. I just like them.
Mine is bigger. Mine is younger. Huh...
For 15 years, South Carolina has been collecting horseshoe crabs for fishing bait. Now, only fishermen with special licenses 8 are allowed to gather crabs for biomedical use and only if they return the crabs alive. Few of us realized just how valuable the horseshoe crab 1 is.
When I first started 37 years ago, we were allowed to harvest them. There was no recording 9; there was nothing. And they became fair game and I was involved with selling them for bait. And then a doctor came down and he said that if I didn't sell bait crabs anymore, he would be interested in the laboratory.
Normal fishing is, as you know, you catch it, you ice it, and you deliver it to the table, and you eat it. The horseshoe crabs we actually catch them, take them to the lab, and they bleed them and we bring them back and release them. So we are borrowing the crabs, this is what we are doing.
Crabs that are borrowed end up a couple of hours away at the Endosafe Laboratories in Charleston. Here in this alien world, they are given a rigorous cleaning to prep them for the process ahead. For the past 30 years, the biomedical industry has been mining the medical equivalent of gold. Endosafe is one of the only four labs in the world that produces a derivative 10 of horseshoe crab blood. Their blood has a clotting 12 agent that's used to detect minute levels of bacteria. But what's truly surprising is the color. The crab's blue blood is an evolutionary 13 gift that's helped them survive the eons.
Male or female? A small male would be good. OK!
Doctor Norman Wainwright has been working with horseshoe crabs for most of his career, studying the remarkable 14 properties of their blood.
The beautiful blue color is a result of its blood containing copper 15 as an oxygen carrying pigment 16 instead of hemoglobin which contains iron. I am adding a suspension of E. coli bacteria.
At the first sign of bacteria, the crab's blood forms a protective clot 11.
Look at that, this is perfect. This is the horseshoe crab cells protecting the animal from infection. Any type of leakage 17 of seawater into their blood system will trigger this response, seal the wound and they actually are proteins in the clot itself that kill the bacteria. They are almost the primitive 18 antibiotics 19.
The phenomenon caught the attention of the biomedical community in the 70s, they've been putting it to work for us ever since. Up to a third of the crab's blood is removed during the process, yet most of them survive. One quart of horseshoe crab blood is worth about 15,000 dollars. It's a multi-million-dollar industry. The clotting agent called Lysate is used to test intravenous drugs for bacteria. No IV drug reaches the market without being tested on horseshoe crab blood. It's an FDA regulation.
Years ago, the only way to screen for toxins 20 dangerous to humans was to use live rabbits. Feverish 21 bunnies revealed contamination and the test was slow. Horseshoe crab blood takes an hour tops and most of the crabs survive the process. Scientists are exploring alternatives that would make bleeding crabs unnecessary. But each day we are finding more ways the horseshoe crab can help us with everything from sutures to contact lenses.
- I can't remember when I last had crab.我不记得上次吃蟹是什么时候了。
- The skin on my face felt as hard as a crab's back.我脸上的皮仿佛僵硬了,就象螃蟹的壳似的。
- As we walked along the seashore we saw lots of tiny crabs. 我们在海岸上散步时看到很多小蟹。 来自《简明英汉词典》
- The fish and crabs scavenge for decaying tissue. 鱼和蟹搜寻腐烂的组织为食。 来自《简明英汉词典》
- We also recognize the diversity and complexity of controlling in fluences in estuaries. 我们也认识到在河湾内控制影响的多样性和复杂性。
- Estuaries also contribute to economy through tourism and fishing. 河口还为人类提供了休闲和教育的场所。
- The fish were madly pushing their way upstream to spawn.鱼群为产卵而疯狂地向上游挤进。
- These fish will lay spawn in about one month from now.这些鱼大约一个月内会产卵。
- Encounter sites have a small chance of spawning a "Commander" NPC. 遭遇战地区有很小的几率遇到NPC指挥官。
- Instantly revives your Champion at your Spawning Pool, 9 minute cooldown. 立即在出生地复活你的英雄,冷却时间9分钟。
- This couple have his knitted out of the hair molted by the pedigreed pets. 这对夫妇拥有他们自己的由纯血种的宠物的毛编制而成的无袖套衫。 来自互联网
- This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
- We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。
- Drivers have ten days' grace to renew their licenses. 驾驶员更换执照有10天的宽限期。 来自《现代汉英综合大词典》
- Jewish firms couldn't get import or export licenses or raw materials. 犹太人的企业得不到进出口许可证或原料。 来自辞典例句
- How long will the recording of the song take?录下这首歌得花多少时间?
- I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。
- His paintings are really quite derivative.他的画实在没有创意。
- Derivative works are far more complicated.派生作品更加复杂。
- Platelets are one of the components required to make blood clot.血小板是血液凝固的必须成分之一。
- The patient's blood refused to clot.病人的血液无法凝结。
- 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
- Life has its own evolutionary process.生命有其自身的进化过程。
- These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
- She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
- These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。
- The students are asked to prove the purity of copper.要求学生们检验铜的纯度。
- Copper is a good medium for the conduction of heat and electricity.铜是热和电的良导体。
- The Romans used natural pigments on their fabrics and walls.古罗马人在织物和墙壁上使用天然颜料。
- Who thought he might know what the skin pigment phenomenon meant.他自认为可能知道皮肤色素出现这种现象到底是怎么回事。
- Large areas of land have been contaminated by the leakage from the nuclear reactor.大片地区都被核反应堆的泄漏物污染了。
- The continuing leakage is the result of the long crack in the pipe.这根管子上的那一条裂缝致使渗漏不断。
- It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
- His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。
- 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。