喜歡雨的味道嗎?

喜歡雨的味道?

If you've lived outside a major city, the smell is instantly recognisable – the earthy scent of petrichor as rain hits dry soil. Now, new research has uncovered why it's not just us humans who are attracted to this incredibly pleasant odour.

如果你住在大城市以外的地方，你會立刻聞到一種叫petrichor的泥土味，那是雨水打在干燥的土壤上的味道。現(xiàn)在，新的研究揭示了為什么不僅僅是我們?nèi)祟悤贿@種令人難以置信的香味所吸引。

That luscious smell we can detect after rain comes from an organic compound called geosmin, which is produced by microbes, including the bacteria genus Streptomyces.

雨后我們能聞到的甜美氣味來自一種叫土臭素的有機(jī)化合物，它是由包括鏈霉菌屬在內(nèi)的微生物產(chǎn)生的。

We also know that Streptomyces releases geosmin when they die, and that humans and other creatures are particularly attuned to it. The question, of course, is - why does this happen?

我們也知道鏈霉菌死后會釋放土臭素，而人類和其他生物對土臭素尤其敏感。當(dāng)然，問題是，為什么會這樣?

An international team of researchers set out to explain why bacteria produce geosmin, and whether any other creatures were able to enjoy the smell as much as we do.

一個國際研究小組著手解釋為什么細(xì)菌會產(chǎn)生土臭素，以及其他生物是否能像我們一樣享受這種氣味。

To investigate possible roles of geosmin and other Streptomyces volatile organic compounds in the context of soil ecosystems, we asked whether the smell of Streptomyces spp. might attract soil-dwelling arthropods, the international team of researchers wrote in their new paper.

“為了研究土臭素和其他鏈霉菌的揮發(fā)性有機(jī)化合物在土壤生態(tài)系統(tǒng)中的可能作用，我們提出了這樣一個問題:鏈霉菌的氣味是否會吸引住在土壤中的節(jié)肢動物，”國際研究團(tuán)隊(duì)在他們的新論文中寫道。

And that's exactly what they found.

這正是他們所發(fā)現(xiàn)的。

In a network of field traps baited with Streptomyces coelicolor colonies, we found significant attraction of springtails (Collembola) compared with control traps.

“在一個以彩色鏈霉菌菌落為誘餌的田間誘捕網(wǎng)中，我們發(fā)現(xiàn)與對照誘捕相比，彈尾具有顯著的吸引力。”

The team did a number of experiments both in the field and in the lab to see the effects of geosmin and another compound called 2-methylisoborneol (2-MIB) on forest creatures, particularly springtails - tiny arthropods with a tail-like appendage, which live in organic materials such as leaf litter on a forest floor.

團(tuán)隊(duì)做了很多實(shí)驗(yàn)場和在實(shí)驗(yàn)室看到geosmin的影響和另一種化合物稱為2-methylisoborneol (2-MIB)森林生物,特別是跳蟲——微型節(jié)肢動物尾巴肢,它生活在有機(jī)材料,如落葉在森林的地面上。

Turns out that springtails are big fans of geosmin. They can sense it with their antennae, are attracted to it, and will feed on the Streptomyces producing it.

事實(shí)證明，彈尾蟲是土臭素的超級粉絲。它們可以用它們的觸須感知它，被它吸引，并以產(chǎn)生它的鏈霉菌為食。

But why would a bacterium go to so much effort just to be slurped up by an arthropod? Although producing a nice smell to get eaten might sound like a bad time for most, Streptomyces actually has a plan.

但為什么細(xì)菌要費(fèi)這么大力氣才能被節(jié)肢動物吃下去呢?雖然對大多數(shù)人來說，產(chǎn)生一種好聞的味道來吃聽起來不是一個好時機(jī)，但鏈霉菌確實(shí)有一個計(jì)劃。

Streptomyces acts, in a lot of ways, like a fungus. It looks a lot like a filamentous fungus, and when it is ready to reproduce, it creates spores, which can spread newborn bacteria far and wide.

鏈霉菌在很多方面都像真菌。它看起來很像絲狀真菌，當(dāng)它準(zhǔn)備繁殖時，它會產(chǎn)生孢子，這些孢子可以將新生的細(xì)菌傳播到四面八方。

But it does need a vector for that spread, which is where the springtails come in.

但它確實(shí)需要一個傳播的矢量，這就是彈尾的作用。

[A springtail] feeds on the Streptomyces colonies and disseminates spores both via faecal pellets and through adherence to its hydrophobic cuticle, the team explains.

“(彈尾蟲)以鏈霉菌菌落為食，通過糞球和附著在疏水性表皮上傳播孢子。”研究小組解釋說。

The results indicate that geosmin and 2-MIB production is an integral part of the sporulation process, completing the Streptomyces life cycle by facilitating dispersal of spores by soil arthropods.

“結(jié)果表明，土臭素和2-MIB的產(chǎn)生是孢子形成過程中不可或缺的一部分，通過促進(jìn)土壤節(jié)肢動物孢子的擴(kuò)散，完成了鏈霉菌的生命周期。”

Next time you smell the rain, you can enjoy the fact that what you're smelling is an entire circle of life in its own little way.

下次當(dāng)你聞到雨的味道時，你就會享受到這樣一個事實(shí):你所聞到的是一個完整的生命循環(huán)。

The research has been published in Nature.

這項(xiàng)研究發(fā)表在《自然》雜志上。