物品有好闻的气味事出有因
文章来源:未知 文章作者:enread 发布时间:2015-01-29 07:10 字体: [ ]  进入论坛
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Antioxidants are natural food ingredients that protect cells from harmful influences. Their main task is to neutralize1 so-called "free radicals2" which are produced in the process of oxidation and which are responsible for cell degeneration. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, and the University of Lund, Sweden, now show that vinegar flies are able to detect these protective substances by using olfactory3 cues. Odors that are exclusively derived4 from antioxidants attract flies, increase feeding behavior and trigger oviposition in female flies. (Current Biology, January 2015) Hydroxycinnamic acids are secondary plant metabolites and important dietary antioxidants. For animals as well as humans, antioxidants are essential components5 of a healthy diet, because they protect the cells and boost the immune system. Notably6, they prevent the emergence7 of too many free radicals, mostly oxygen compounds, and therefore a metabolic8 condition, which is generally called oxidative stress. If an organism suffers from oxidative stress, free radicals attack its cells and weaken its immune system. In fruit flies, oxidative stress is induced by immune responses to toxins9 produced by pathogens in the food.
 
Hydroxycinnamic acids are found in high amounts in fruit. Since fruit is the preferred breeding substrate of fruit flies, scientists in the Department of Evolutionary10 Neuroethology at the Max-Planck-Institute for Chemical Ecology in Jena, Germany, took a closer look at these substances and their possible effect on the flies.
 
Fruit flies are not able to smell hydroxycinnamic acids directly. However, yeasts12 metabolize the antioxidants and produce ethylphenols. These volatile13 substances activate14 targeted olfactory neurons housed on the maxillary palps of the fruit flies, which express the odorant receptor Or71a. Interestingly, fly larvae15 which are also attracted by yeasts enriched with hydroxycinnamic acids using ethylphenols as olfactory cues, employ another odorant receptor for binding16 ethylphenols: Or94b, which is exclusively found in larvae, and which is co-expressed with Or94a, a receptor binding a general yeast11 odor. Because flies cannot smell the antioxidants directly, ethylphenols provide reliable cues for the presence of these protective compounds in the food. The perception of these odorant signals has a direct impact of the flies' behavior: They are attracted by the odor sources, show increased feeding behavior and choose oviposition sites where ethylphenols indicate that antioxidants are present in the breeding substrate.
 
"This form of olfactory proxy17 detection is not only a phenomenon in insects. It has also been shown in humans, that odors that we perceive as pleasant or appetizing, are in fact derived from important and healthy nutrients18, such as essential amino acids, fatty acids and vitamins," Marcus Stensmyr explains. The scientist, who carried out the studies in the Department of Evolutionary Neuroethology together with his colleagues, has recently moved to a position as senior lecturer at the University of Lund.
 
These findings demonstrate a further example of an individual neuronal pathway, which has a profound effect on the flies: from the odorant signal to olfactory neurons and dedicated19 odorant receptors to behavior. The ethylphenol pathway as an olfactory proxy detection of dietary antioxidants shows yet another facet20 of the complex odor-guided behavior in fruit flies. The scientists will now try to identify further neural21 pathways involved in the detection of essential nutrients, which ultimately trigger the flies' behavior.


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1 neutralize g5hzm     
v.使失效、抵消,使中和
参考例句:
  • Nothing could neutralize its good effects.没有什么能抵消它所产生的好影响。
  • Acids neutralize alkalis and vice versa.酸能使碱中和碱,亦能使酸中和。
2 radicals 5c853925d2a610c29b107b916c89076e     
n.激进分子( radical的名词复数 );根基;基本原理;[数学]根数
参考例句:
  • Some militant leaders want to merge with white radicals. 一些好斗的领导人要和白人中的激进派联合。 来自《简明英汉词典》
  • The worry is that the radicals will grow more intransigent. 现在人们担忧激进分子会变得更加不妥协。 来自辞典例句
3 olfactory Z5EzW     
adj.嗅觉的
参考例句:
  • He is to develop a sensor to substitute for the olfactory abilities of dogs.克罗克将研制一种传感器用以代替狗的嗅觉功能。
  • Based on these findings, Keller suspects that each person has an olfactory blind spot.根据这些发现,凯勒推断,每个人都有一个嗅觉盲区。
4 derived 6cddb7353e699051a384686b6b3ff1e2     
vi.起源;由来;衍生;导出v.得到( derive的过去式和过去分词 );(从…中)得到获得;源于;(从…中)提取
参考例句:
  • Many English words are derived from Latin and Greek. 英语很多词源出于拉丁文和希腊文。 来自《简明英汉词典》
  • He derived his enthusiasm for literature from his father. 他对文学的爱好是受他父亲的影响。 来自《简明英汉词典》
5 components 4725dcf446a342f1473a8228e42dfa48     
(机器、设备等的)构成要素,零件,成分; 成分( component的名词复数 ); [物理化学]组分; [数学]分量; (混合物的)组成部分
参考例句:
  • the components of a machine 机器部件
  • Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。
6 notably 1HEx9     
adv.值得注意地,显著地,尤其地,特别地
参考例句:
  • Many students were absent,notably the monitor.许多学生缺席,特别是连班长也没来。
  • A notably short,silver-haired man,he plays basketball with his staff several times a week.他个子明显较为矮小,一头银发,每周都会和他的员工一起打几次篮球。
7 emergence 5p3xr     
n.浮现,显现,出现,(植物)突出体
参考例句:
  • The last decade saw the emergence of a dynamic economy.最近10年见证了经济增长的姿态。
  • Language emerges and develops with the emergence and development of society.语言是随着社会的产生而产生,随着社会的发展而发展的。
8 metabolic 2R4z1     
adj.新陈代谢的
参考例句:
  • Impressive metabolic alternations have been undergone during embryogenesis.在胚胎发生期间经历了深刻的代谢变化。
  • A number of intoxicants are associated with metabolic acidosis.许多毒性物质可引起代谢性酸中毒。
9 toxins 18c3f40d432ba8dc33bad8fb82873ea8     
n.毒素( toxin的名词复数 )
参考例句:
  • The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
  • Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》
10 evolutionary Ctqz7m     
adj.进化的;演化的,演变的;[生]进化论的
参考例句:
  • 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。
11 yeast 7VIzu     
n.酵母;酵母片;泡沫;v.发酵;起泡沫
参考例句:
  • Yeast can be used in making beer and bread.酵母可用于酿啤酒和发面包。
  • The yeast began to work.酵母开始发酵。
12 yeasts 6b2eca0ad59a93e429f62e7251090f31     
酵母( yeast的名词复数 ); 酵母菌; 发面饼; 发酵粉
参考例句:
  • The basidiospores proliperate in a manner comparable to the multiplication of yeasts. 担孢子以一种可与酵母繁殖相比拟的方式进行增殖。
  • Wine yeasts can grow in sweet wines even after bottling. 装瓶以后葡萄酒酵母也能在甜葡萄酒中生长。
13 volatile tLQzQ     
adj.反复无常的,挥发性的,稍纵即逝的,脾气火爆的;n.挥发性物质
参考例句:
  • With the markets being so volatile,investments are at great risk.由于市场那么变化不定,投资冒着很大的风险。
  • His character was weak and volatile.他这个人意志薄弱,喜怒无常。
14 activate UJ2y0     
vt.使活动起来,使开始起作用
参考例句:
  • We must activate the youth to study.我们要激励青年去学习。
  • These push buttons can activate the elevator.这些按钮能启动电梯。
15 larvae w2CxP     
n.幼虫
参考例句:
  • Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
  • The larvae prey upon small aphids.这种幼虫以小蚜虫为食。
16 binding 2yEzWb     
有约束力的,有效的,应遵守的
参考例句:
  • The contract was not signed and has no binding force. 合同没有签署因而没有约束力。
  • Both sides have agreed that the arbitration will be binding. 双方都赞同仲裁具有约束力。
17 proxy yRXxN     
n.代理权,代表权;(对代理人的)委托书;代理人
参考例句:
  • You may appoint a proxy to vote for you.你可以委托他人代你投票。
  • We enclose a form of proxy for use at the Annual General Meeting.我们附上委任年度大会代表的表格。
18 nutrients 6a1e1ed248a3ac49744c39cc962fb607     
n.(食品或化学品)营养物,营养品( nutrient的名词复数 )
参考例句:
  • a lack of essential nutrients 基本营养的缺乏
  • Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》
19 dedicated duHzy2     
adj.一心一意的;献身的;热诚的
参考例句:
  • He dedicated his life to the cause of education.他献身于教育事业。
  • His whole energies are dedicated to improve the design.他的全部精力都放在改进这项设计上了。
20 facet wzXym     
n.(问题等的)一个方面;(多面体的)面
参考例句:
  • He has perfected himself in every facet of his job.他已使自己对工作的各个方面都得心应手。
  • Every facet of college life is fascinating.大学生活的每个方面都令人兴奋。
21 neural DnXzFt     
adj.神经的,神经系统的
参考例句:
  • The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
  • The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。
TAG标签: cells fruit immune
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