June 10, 2014 12:08 PM
A new way to fight malaria aims to eliminate the female mosquitoes that spread the deadly disease.
Scientists have developed mosquitoes that produce almost exclusively male offspring.
Females are the ones that bite. And they are the ones that produce more mosquitoes. The researchers say their technique could wipe out mosquito populations in a few months, without the use of insecticides.
World’s biggest killers
“Mosquitoes have been labeled as the most virulent animal in the world,” said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine. “More people die of mosquito-transmitted infections than they do of almost any other type of illness.”
Spraying insecticides is one of the most effective ways to control them, but spraying comes with downsides. It can kill bees and other good insects, and cause environmental damage. And mosquitoes eventually develop resistance to the pesticide.
貝勒醫學院的熱帶病學(tropical medicine)學院的院長說，「一直以來蚊子都被認定是(…labeled as)世界上最具毒性的(virulent)動物，基本上可以說，死於(die of . . .)蚊子傳播的傳染病(infection)的人數高於任何其它疾病。」
So Imperial College London researcher Nikolai Windbichler and colleagues are trying a different approach. “We found an Achilles’ heel of these mosquitoes,” he said.
The insects have around 400 copies of a particular gene on the X chromosome. That’s the chromosome that carries the traits making the insects female.
A creature called a slime mold produces a protein that cuts that gene in one specific place.
The Imperial College London team introduced that slime mold protein into mosquitoes using genetic engineering.
It is designed to turn on when the mosquitoes make sperm. When it does, it cuts the X chromosome in 400 places.
“You can imagine, that’s pretty bad for a chromosome,” Windbichler said. “It gets destroyed. It cannot be passed on to the next generation.”
That leaves only male offspring. And those offspring also would only produce male offspring. Eventually the population would crash.
研究人員表示，「不難想像，這對染色體絕非好事。染色體被破壞了，也無法遺傳給(be passed on to . . .)下一代。」
More Tests Needed
The research is published in Nature Communications.
They have more tests to do to make sure the method is safe and effective. But Windbichler says it beats the alternative.
“If you compare what we are doing to, for example, insecticides, which target any insect species out there, our method is very specific,” Windbichler said. “There may be hundreds of mosquito species in the environment, but our method really only would target that one.”
Baylor’s Peter Hotez, who was not involved in the research, calls it an interesting and exciting finding. But, he added, “It’s still a very early stage.”
Meanwhile, he says, it will take more than just designer mosquitoes to beat malaria.
New drugs and vaccines will be needed, along with bed nets and clearing their breeding grounds with good, old-fashioned puddle-draining.
一位並無參與本研究的熱帶病學專家認為，這是個有趣而且令人振奮的發現，但仍只是初期階段。他認為就現階段要打敗瘧疾不能只靠這種特別改造的蚊子。除了新的藥物與疫苗之外，也還要(along with)蚊帳(bed net)與傳統上最有效的清理蚊子孳生地(breeding grounds)的方式，也就是放乾小水窪(puddle)的積水。
eliminate (v) 消除
wipe out (v phr) 消滅；徹底摧毀 xxxxxoffspring (n) 子孫;後代
virulent (a) 劇毒的；致命的 xxxxxxxxx dean (n) (大學的)教務長；學院院長
downside (n) 不利之處；可能的缺點 x resistance (n) 抵抗；抗藥性
Achilles’ heel (n phr) 致命的弱點XXXXX典故來自希臘神話。在神話中，阿基里斯的母親抓著剛出生的阿基里斯的腳踝，將其浸泡在斯提克斯冥河(River Styx)中以求能刀槍不入。但沒泡到水的腳踝，卻成了讓阿基里斯致命的弱點。 xxxxxxxxxxxxxx ix
trait (n) 特徵，特點xxxxxxxxxxxxxxxx shredder (n) 碎紙機 xxx
alternative (n) 替代方案xxxxxxxxxxxxxalong with (prep phr) 和…一起
Check your vocabulary!
Fill in the blanks with a word or phrase from the list above. Make necessary changes. After you finish, select the text below to reveal the hidden answers.
1. Much of the documentary evidence against her had been put through the shredder before she was arrested.
2. Whole villages were wiped out by the floods.
3. Vanity is his Achilles' heel.
4. Digital cell phones offer more security, but the downside is that they have less power.
5. The credit card eliminates the need for cash or cheques.
6. Jim's two most pleasing traits are generosity and energy.