【外刊D66】科学新发现：蚊子为什么会咬人？
今日导读
夏天来了，又到了蚊子来势汹汹的季节。晚上睡觉时，是不是有蚊子在耳边嗡嗡叫吵得你烦躁无比？一不留神还会被叮上一个奇痒无比的包？不少人都很好奇，蚊子究竟是怎么“盯上”自己的？近日，佛罗里达国际大学的研究人员在国际学术期刊《当代生物学》上发布了一项最新研究成果，阐明了蚊子如何探测到人体汗液中乳酸的原理。这究竟是个什么样的原理，又对人类有什么意义呢？让我们跟着 Karen 老师一起看看《法新社》的这篇报道。
新闻原文
Scientists discover how mosquitoes detect human sweat
AFP
Scientists have known for decades that mosquitoes are attracted to the lactic acid contained in human sweat, but in the era before advanced genetics, the precise mechanism had remained a mystery.
Now, a team of researchers at Florida International University have discovered the olfactory receptor that allows the disease-carrying insects to hone in on our odor — and how to switch it off.
They published their work on the Aedes aegypti mosquitoes, known for spreading deadly illnesses like Zika, dengue and yellow fever, in the journal Current Biology on Thursday.
The team, led by FIU biologist Matthew DeGennaro, identified the guilty receptor as Ionotropic Receptor 8a, or simply IR8a, through a process of elimination that began in 2013 when DeGennaro was able to create the world's first mutant mosquito, removing a gene to investigate how its absence affected the insect.
Tasked with investigating IR8a, DeGennaro's PhD student Joshua Raji began by carrying out an exposure experiment using his own arm, and found the mutant mosquitoes were significantly less attracted to him than wild ones.
The outcome was confirmed through testing on 14 additional subjects.
"People have been looking for a receptor for lactic acid since the 1960s, " DeGennaro told AFP.
The findings could offer a roadmap for a new generation of attractants that lure adult specimens into traps for population control, as well as advanced repellants that make people invisible to mosquitoes — though that could be some way away.
"It'll take years, but we are definitely a step closer, " said DeGennaro.
带着问题听讲解
埃及伊蚊会传播哪些疾病？
如何理解 hone in on 这个短语？
本文中的科学家是用什么方法来降低蚊子对人的探测能力的？
新闻正文
Scientists discover how mosquitoes detecthuman sweat
蚊子是如何探测到人体汗液的？科学家解开谜题
Scientists have known for decades that mosquitoes are attracted to the lactic acid contained in human sweat, but in the era before advanced genetics, the precise mechanism had remained a mystery.
几十年来，科学家们都知道蚊子会被人体汗液中所含的乳酸所吸引，但在高级遗传学出现之前，其确切原理一直是个谜。
Now, a team of researchers at Florida International University have discovered the olfactoryreceptor that allows the disease-carrying insects to hone in on our odor — and how to switch it off.
有一种嗅觉受体可以让携带疾病的蚊子锁定我们的气味，现在，佛罗里达国际大学的一个研究人员小组发现了这种嗅觉受体，并且找到了关闭受体的方法。
They published their work on the Aedes aegypti mosquitoes, known for spreading deadly illnesses like Zika, dengue and yellow fever, in the journal Current Biology on Thursday.
周四，他们在《当代生物学》期刊上发表了关于埃及伊蚊的研究成果。埃及伊蚊以传播寨卡病毒、登革热和黄热病等致命疾病而闻名。
The team, led by FIU biologist Matthew DeGennaro, identified the guilty receptor as Ionotropic Receptor 8a, or simply IR8a, through a process of eliminationthat began in 2013 when DeGennaro was able to create the world's first mutant mosquito, removing a gene to investigate how its absence affected the insect.
这个研究小组由佛罗里达国际大学的生物学家马修·德根纳罗领导。小组通过排除法，确定了这种罪魁祸首的受体为亲离子受体 8a，简称 IR8a。这个排除法实验从 2013 年就开始了，当时德根纳罗移除了（蚊子的）一种基因，得以创造出了世界上第一只变体蚊子，为的是研究缺少这种基因对蚊子的影响。
Tasked with investigating IR8a, DeGennaro's PhD student Joshua Raji began by carrying out an exposure experiment using his own arm, and found the mutant mosquitoes were significantly less attracted to him than wild ones.
马修·德根纳罗的博士生约书亚·拉吉被指派研究 IR8a，他先用自己的手臂做了一个暴露实验，结果发现自己对变体蚊子的吸引力明显小于野生蚊子。
The outcome was confirmed through testing on 14 additional subjects.
对另外 14 名受试者的测试也证实了这一结果。
"People have been looking for a receptor for lactic acid since the 1960s," DeGennaro told AFP.
“自 20 世纪 60 年代以来，人们就一直在寻找（蚊子的）乳酸受体，”德根纳罗告诉法新社。
The findings could offer a roadmap for a new generation of attractants that lure adult specimens into traps for population control, as well as advanced repellants that make people invisible to mosquitoes — though that could be some way away.
这些研究可以为研制新一代昆虫引诱剂和先进驱蚊剂提供方向，引诱剂可以引诱成年昆虫进入陷阱，以控制种群数量，而驱蚊剂则能使人们不被蚊子探测到——尽管这可能还需要一段时间。
"It'll take years, but we are definitely a step closer," said DeGennaro.
德根纳罗说：“这将需要好几年的时间，但毫无疑问我们离目标更近了一步。”
重点词汇
mosquito
/məˈskiːtoʊ/
n. 蚊
detect
/dɪˈtekt/
v. 探测，检测，测出
近义词：discover
搭配短语：detect symptoms of the disease（检测到疾病征兆）；detect radiation（探测到辐射）
lactic acid
乳酸
相关词汇：lactic（adj. 乳汁的）
相关词汇：acid（n. 酸；adj. 酸味的；说话尖酸的）
acid 搭配短语：acid fruit（酸的水果）；acidremark（尖酸刻薄的话语）
mechanism
/ˈmekənɪzəm/
n. 机械零件；运行机制
英文释义： the way that something works
相关词汇：machine
搭配短语：the mechanism of the brain（大脑的运行机制）；the immune system's mechanism（免疫系统的运行原理）
olfactory
/ɑːlˈfæktəri/
adj. 嗅觉的
搭配短语：the olfactory cells in the nose（鼻腔内的嗅觉细胞）
receptor
/rɪˈseptər/
n. 感受器；受体
相关词汇：receive（v. 接受）
hone in on
聚焦、锁定在某物上
同义词：home in on; zero in on
英文释义：to focus or concentrate on something
例句：The missile honed in on the ship.
odor
/ˈoʊdər/
n. 气味
近义词：smell (n. 气味)
搭配短语：the odor of rotting fruit（腐烂水果的气味）；the odor of chocolate（巧克力的香味）
英文释义：a quality of something that stimulates the olfactory organ
process of elimination
排除法
mutant
/ˈmjuːtənt/
adj. 变体的，变异的
词性拓展：n. 突变体；变种人
task sb. with sth.
给某人委派某项任务
subject
/ˈsʌbdʒekt/
n. 接受试验者；实验对象
roadmap
/ˈroʊd mæp/
n. 路线图；计划，指导
同义词：road map
英文释义：a plan or set of instructions that makes it easier for someone to do something
近义词：guideline
attractant
/əˈtræktənt/
n. 引诱剂
词根词缀：attract（v. 吸引）；-ant（用作…的东西）
repellant
/rɪˈpelənt/
n. 驱虫剂，驱蚊剂
词根词缀：repel（v. 驱赶，击退）；-ant（用作…的东西）
补充词汇知识
era
n. 时代
搭配短语：the era of artificial intelligence
例句：The era of 5G networks is dawning.
odor
n. 气味
英文释义：a quality of something that stimulates the olfactory organ
switch off
关闭电灯或机器；关闭（受体）
on
prep. 关于
搭配短语：a book on insects（一本关于昆虫的书）
例句：Her thesis is on American literature.
identify A as B
认出 A 就是 B
近义词：find; discover
test on
在某人身上实验
some way away
还需要一段时间
相关词汇：way（n. 一段距离或时间）；away（adv. 距离某地有多远）
way 英文释义：distance or a period of time
长难句解析
The team, led by FIU biologist Matthew DeGennaro, identified the guilty receptor as Ionotropic Receptor 8a, or simply IR8a, through a process of elimination that began in 2013 when DeGennaro was able to create the world's first mutant mosquito, removing a gene to investigate how its absence affected the insect.
这个研究小组由 FIU 的生物学家马修·德根纳罗领导。小组通过一个（受体）去除过程，确定了这种罪魁祸首的受体为亲离子受体 8a，简称 IR8a。这个基因去除研究开始于 2013 年，当时德根纳罗通过移除（蚊子的）一种基因，创造出了世界上第一只变体蚊子，以研究缺少这种基因对蚊子的影响。
主句为 The team identified the guilty receptor as Ionotropic Receptor 8a.。插入语 led by FIU biologist Matthew DeGennaro 为 the team 的后置定语。介词短语 through a process of elimination 说明了找到受体的方法。后面 that 引导的定语从句补充了开始研究的时间，其中又包含了一个由 when 引导的时间状语从句，说明当时的研究过程。句末 removing a gene to investigate how its absence affected the insect 为状语，阐明了研究的具体方法，其中 how its absense affected the insect 为 how 引导的名词性从句当 investigate 的宾语。
The findings could offer a roadmap for a new generation of attractants that lure adult specimens into traps for population control, as well as advanced repellants that make people invisible to mosquitoes — though that could be some way away.
这些研究可以为研制新一代（昆虫）引诱剂和先进驱蚊剂提供了方向，引诱剂可以引诱成年昆虫进入陷阱，以控制种群数量，而驱蚊剂则能使人们不被蚊子探测到——尽管这可能还需要一段时间。
句子主干为 The findings could offer a roadmap for A as well as B，其中 A 为 a new generation of attractants，B 为 advanced repellants。attractants 和 repellants 后面由 that 引导的两个定语从句分别说明了它们各自的功能。破折号后的部分为 though 引导的让步状语从句。
文化知识
advanced genetics
高级遗传学，又可以理解为“非孟德尔遗传学“（non-Mendilian genetics），研究的是不服从孟德尔遗传定律的遗传现象。它主要研究的是 mtDNA（线粒体 DNA）。线粒体 DNA 是线粒体中的遗传物质，通过卵细胞传递，所以只能由母亲传给自己的女儿。
而新闻中的 the era of advanced genetics 其实指的是“高级遗传学的时代”，从 1910 年到现在，遗传学的发展大致可以分为三个时期：细胞遗传学时期、微生物遗传学时期和分子遗传学时期。新闻中，DeGennaro 教授研究蚊子基因的时候采用的是“分子遗传学”，也就是最新的一种遗传学研究方法。
参考链接：
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一句话总结新闻
本期《法新社》讲述了科学家们发现蚊子体内的嗅觉受体使它们能够闻到人体汗液气味，该研究为研制新一代昆虫引诱剂和驱蚊剂提供了方向。
拓展阅读
蚊子爱叮什么样的人？
蚊子爱叮什么样的人？对于这个问题，人们的看法五花八门。有人认为是 O 型血的人，有人认为是性激素水平高的人，还有人认为是“血甜”的人。那么，科学给我们的答案是什么呢？研究表明，以下几种人群更受蚊子“欢迎”：
汗腺发达、体温较高的人。一方面，汗腺发达的人所排出的大量汗液会提高体表的乳酸值，从而较容易吸引蚊子。另一方面，蚊子触角里的受热体使得它对温度十分敏感，而汗量多、易出汗的人肌体散热较快，因此也会对蚊子产生吸引力。这就能解释为什么皮肤粗糙、毛孔粗大的人更容易受到蚊子叮咬，因为这类人往往容易流汗，排出的汗液等分泌物较多。
运动量大或呼吸频率较快的人。在剧烈运动后，人体呼吸会加快，呼出的大量二氧化碳会在人体周围形成温暖的气流，从而吸引蚊子。肺活量大、呼吸频率快的人也因此更容易被蚊子叮咬。
穿深色衣服的人。蚊子有趋暗的习性，喜欢在弱光环境下吸血，身穿深色衣服会为蚊子提供一个有利的“作案”环境。同理，蚊子也爱叮咬肤色较黑或肤色发红的人。此外，正如上文所说的，蚊子对温度敏感，而深色衣物的吸热能力较强，也会对蚊子产生极大的吸引力。
化妆的人。目前市面上的化妆品大多含有硬脂酸，而硬脂酸是吸引蚊子的重要因素之一，因此使用发胶、面霜等化妆品会增加被蚊子叮咬的几率。但蚊子也会对一些气味避而远之，如大蒜、月桂叶、香茅等。
另外，对于蚊子是否对某些血型有趋向性，目前没有科学依据能够证明。
