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人蚊大战,用转基因毒蘑菇杀死传播疟疾的蚊子&物理学中破坏热力学第二定律的小妖怪-麦克斯韦妖

已有 1630 次阅读 2019-6-5 16:12 |系统分类:科普集锦


人蚊大战,用转基因毒蘑菇杀死传播疟疾的蚊子&热力学第二定律与麦克斯韦妖.pdf



                原汁原味的Sci & Tech News weekly

Volume 5  19年6月5日

Editor: Dr. Collin F. Hu

卷首语:本期在Health领域,将给大家介绍一种杀死传播疟疾的蚊子的新的方法——使用基因改造的毒蘑菇来毒死能传播疟疾的蚊子。

有谁不讨厌蚊子呢?在夏日凉风习习的晚上和家人一起去乘凉,玩耍,讲故事是一件很浪漫的事情,可是这种气氛只需要几只蚊子就可以破坏。而且,据我的经验,蚊子偏爱小鲜肉,所以总是我女儿身上有一个个的大包。

蚊子之可恶当然远不止是不解风情了。它在非洲更是一种致命的杀手,它能传播疟疾,传播的登革热,传播塞卡病毒,每年会杀死40万人,名副其实的最危险动物。因此,人和蚊子已是势不两立,不共戴天。

在我读大学的时候,也许是年少无知吧,曾经认为所有物种,生而平等。近年来,在人蚊大战开始后,变为担心蚊子这个物种灭绝后,是否会引起生态系统的波动。在2010年,看到一篇文章,一些有影响力的生物学家认为蚊子灭绝了,生态系统的变化就像人打个嗝一样,不会有大的波动。

现在科学家已经发现了多种消灭蚊子的方法,曾经看到物理学家用激光打蚊子。随着一束束激光的发射,看到一个个正在空中飞行的蚊子,发出一缕烟,被打下来,感觉很爽。但其实,生物学家的方法更有效(对蚊子来说更恶毒)。几年前曾经读到过一篇文章,说是用基因改造过的雄蚊子与野外的雌蚊子交配,其后代存活不到成年就会死掉。生物学家在巴西的某地曾释放过一批这种转基因的蚊子,当地蚊子的数量好像是减少了70%,这个实验的后续进展我没有跟进。最近,在比尔盖茨的基金推动下,用一种叫做“基因驱动”的方法,可能与最新的Crispr-cas9基因编辑技术相关,据说3-5年内,会让蚊子从地球上消失,连同疟疾,登革热,塞卡一起滚蛋。这篇文章也是人蚊大战的一部分,但用的是另外一种方法,目前还在研究阶段。

人蚊大战的号角已经吹响,虽然这场战争中,蚊子从自然选择中也慢慢发展出抗药性,使得抗疟疾的青蒿素如果单独使用效果会降低,必须和其它药剂一起使用。但人类现在主宰了这场战争,特别是随着现在基因技术的发展。也许再过5年,再见了,蚊子!来自西方的科学就是非常强悍的。

在Physics领域,我将给大家介绍一下物理学上非常著名且重要的Maxwell demon。科学必须被实验所检验,这是基本的科学精神。但有时候,一下子找不到实验的方法,或者实验的设备达不到要求,于是就有了思想实验,只在脑袋里面存在的实验。爱因斯坦就是此中高手,他构思相对论的时候,经常想到的就是两个布满时钟的火车,相对运动的速度接近光速。

今天给大家介绍的Maxwell demon的创造者就是那个写下了著名的Maxwell方程组,从而开启了人类电气时代的人。这个小妖怪的创造是为了说明热力学第二定律的一个局限性,它的统计性。利用这个小妖怪,可以让一盒子已经温度均一的气体,一边冷,一边热,从而可以做功,比如推动火车前进。

现在看来,这个小妖怪的出现,让人第一次感到物理学与信息学的深层次的关系,也让我们就认识了,科学是非常有趣的

Health

用基因改造的蘑菇可以迅速的杀死99%的传播疟疾病毒的蚊子。这种蘑菇的基因改造是受到一种能够毒死蚊子的蜘蛛的毒液的启发。把这种蘑菇长出的孢子涂抹在蚊子经常光顾的地方,就可以让蚊子“仿佛被蜘蛛咬到一样”,蚊子体内会如同感受到蜘蛛的毒液。

当然,这种方法有一个局限性,也是科学家正在谨慎研究的一个问题,它对生态环境,包括人,还有那些影响?现在已经发现这种毒蘑菇不会对蜜蜂等昆虫产生影响。在这项研究中,科学家用蚊帐围住一些区域,制造出一些人为的自然区域,就是希望这种基因改造的蘑菇不会对其生态环境造成。

GM fungus rapidly kills 99% of malaria mosquitoes, study suggests

By James Gallagher 31 May 2019

_107168597_c0093034-feeding_mosquito-spl.jpg

[Summary] A fungus - genetically enhanced to produce spider toxin - can rapidly kill huge numbers of the mosquitoes that spread malaria, a study suggests.

enhanced:增强;提升

“a study suggests” 一项研究表明。

 

[How it matters?] Trials, which took place in Burkina Faso, showed mosquito populations collapsed by 99% within 45 days. The researchers say their aim is not to make the insects extinct but to help stop the spread of malaria. The disease, which is spread when female mosquitoes drink blood, kills more than 400,000 people per year. Worldwide, there are about 219 million cases of malaria each year.

“Trials” 实验;

“The researchers say their aim is not to make the insects extinct but to help stop the spread of malaria.”不明白为什么作者不敢直接说他们的目的就是”wipe out the mosquitoes”,也许反对的声音太大吧。

 

[How to do it?] They turned to a toxin found in the venom of a species of funnel-web spider in Australia. The genetic instructions for making the toxin were added to the fungus's own genetic code so it would start making the toxin once it was inside a mosquito. The next step was to test the fungus in as close to real-world conditions as possible. A 6,500-sq-ft fake village - complete with plants, huts, water sources and food for the mosquitoes - was set up in Burkina Faso. It was surrounded by a double layer of mosquito netting to prevent anything escaping. The fungal spores were mixed with sesame oil and wiped on to black cotton sheets. The mosquitoes had to land on the sheets to be exposed to the deadly fungus. The researchers started the experiments with 1,500 mosquitoes.

venom:毒液;

added to the fungus's own genetic code”,基因改造的过程;

“6,500-sq-ft” 6500 Square Foot (ft²) = 603.86976 Square Meter (m²)

real-world conditions”真实世界的条件;

可能现实世界的情况比实验中预想的更加复杂,不知道在真实的世界中,这个实验是否还有这么好的实验结果。

 

[The results] The results, published in the journal Science, showed numbers soared when the insects were left alone. But when the spider-toxin fungus was used, there were just 13 mosquitoes left after 45 days. Tests also showed the fungus was specific to these mosquitoes and did not affect other insects such as bees. … New tools are needed to tackle malaria as mosquitoes are becoming resistant to insecticides. The World Health Organization has warned that cases are now increasing in the 10 worst affected countries in Africa.

soared:飙升;快速上升;

specific to: 特别针对;

resistant to insecticides”对杀虫剂的抗药性;这是蚊子在进化过程中发展出来的特征。

World Health Organization:世界卫生组织;

 

[Comments] Commenting on the findings, Prof Michael Bonsall, from the University of Oxford, said: "Neat - this is a super-exciting study." "Proportionate bio-safety regulations are needed to ensure that the viability of this and other approaches for vector [mosquito] control using genetic methods are not lost through overly zealous restrictions." Dr Tony Nolan, from the Liverpool School of Tropical Medicine, added: "These results are encouraging. "We need new and complementary tools to augment existing control methods, which are being affected by the development of insecticide-resistance."

在BBC新闻中,为了保证新闻的客观,中立,往往邀请一些第三方人士对研究做出报道。可以看出,这些人对这个实验都是赞赏状态,但是对其在真实世界中的应用提到应该有一些监管措施。

 

推荐读13遍的英语句子:

1.   A fungus - genetically enhanced to produce spider toxin - can rapidly kill huge numbers of the mosquitoes that spread malaria, a study suggests.

2.   The researchers say their aim is not to make the insects extinct but to help stop the spread of malaria.

3.   The next step was to test the fungus in as close to real-world conditions as possible.

4.   The mosquitoes had to land on the sheets to be exposed to the deadly fungus.

5.   Tests also showed the fungus was specific to these mosquitoes and did not affect other insects such as bees.

6.   New tools are needed to tackle malaria as mosquitoes are becoming resistant to insecticides.

7.   Neat - this is a super-exciting study.

 

Physics:        

物理学中,一个有智能的微小生物会破坏热力学第二定律。如下图显示的,本来一盒子温度如室温,而且均一的气体在这个小妖怪的作用下,一边可以当冰箱用,另一边,可以烧开一壶开水。一句话,小妖怪从气体分子无序的动能中产生了可以使用的能量。

对这样一个小妖怪,传统的物理回答,她是不存在的。有什么物理器械能够判断出分子运动的速度,且作出要不要关门的决定。所以,尽管有这个小妖怪存在,热力学第二定律并没有受到影响。

只不过,在近些年的发展中,尤其是在生物系统中,这个小妖怪再次引起物理学家的注意。生命系统需要很多的这种小妖怪(或生物学大分子)来打破热力学的平衡,从而创造出五彩斑斓的生命。

这个小妖怪也再一次提示物理学家们,物理学和信息科学在深层次上有密切的关联。

Maxwell’s demon

From Wiki 3 June 2019

Maxwells-Demon.jpg

Maxwell's demon is a thought experiment created by the physicist James Clerk Maxwell in 1867 in which he suggested how the second law of thermodynamics might hypothetically be violated. In the thought experiment, a demon controls a small door between two chambers of gas. As individual gas molecules approach the door, the demon quickly opens and shuts the door so that only fast molecules are passed into one of the chambers, while only slow molecules are passed into the other. Because faster molecules are hotter, the demon's behaviour causes one chamber to warm up and the other to cool down, thereby decreasing entropy and violating the second law of thermodynamics. This thought experiment has provoked debate and theoretical work on the relation between thermodynamics and information theory extending to the present day, with a number of scientists arguing that theoretical considerations rule out any practical device violating the second law in this way.

 

推荐读13遍的英语句子:

1, Maxwell's demon is a thought experiment created by the physicist James Clerk Maxwell in 1867 in which he suggested how the second law of thermodynamics might hypothetically be violated.

2, This thought experiment has provoked debate and theoretical work on the relation between thermodynamics and information theory extending to the present day, with a number of scientists arguing that theoretical considerations rule out any practical device violating the second law in this way.

James Clerk Maxwell:麦克斯韦,可以说是仅次于牛顿和爱因斯坦的伟大理论物理学家。比钻石还珍贵的麦克斯韦方程组直接把人类从机器时代带到了电气时代。

provoke:激发;引起;



人蚊大战,用转基因毒蘑菇杀死传播疟疾的蚊子&热力学第二定律与麦克斯韦妖.pdf




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