英語聽力文摘 神奇的“鼻子”
精子靠“嗅覺”發(fā)現(xiàn)卵子
Scientists who study human sperm have long wondered whether human sperm could somehow sense the presence of an egg. Then, just about a decade ago, it was discovered that sperm have proteins on them that react to the presence of certain chemicals. In fact, these are the same molecules used by nerve cells in your nose when you sniff out a scent.
Nothing that looks like a nose of course, but these chemical-sensing proteins act like noses. Researchers call these sensory devices “olfactory receptors.” More recent studies have started figuring out what kind of chemical attracts a sperm.
The most effective spermattractor is called “bourgeonal.” Bourgeonal is a floral scent. When sperm sense the presence of bourgeonal, they race toward it. Their speed goes from eighteen point three micrometers per second up to a whopping thirty point one. The most likely thing is that bourgeonal just happens to be structurally similar to another chemical produced by a female egg.
研究人類精子的科學(xué)家們長(zhǎng)期以來都很疑惑：精子是否能以某種方式察覺到卵子的存在。大約就在十多年前，人們發(fā)現(xiàn)精子本身含有一些蛋白質(zhì)對(duì)某些特定的化學(xué)物質(zhì)會(huì)產(chǎn)生反應(yīng)。實(shí)際上，那些就是我們鼻子聞氣味時(shí)需要的神經(jīng)細(xì)胞。
當(dāng)然不是真正的鼻子，但可以嗅到化學(xué)五的蛋白質(zhì)就像鼻子一樣。研究人員把這些感知工具叫做“嗅覺感受器”。很多近代的研究已經(jīng)開始弄清楚吸引精子的是那種化學(xué)物質(zhì)。
最有效的精子吸引子叫bourgeonal。Bourgeonal一種花香化合物。當(dāng)精子嗅到這種味道，就會(huì)迅速向它移動(dòng)。精子的速度從每秒18.3微米上升到30.1微米。最有可能的是， bourgeonal與由卵子產(chǎn)生的一種化學(xué)物在結(jié)構(gòu)上是相似的。
