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?，F(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，”國際研究團隊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.

團隊做了很多實驗場和在實驗室看到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.

但為什么細菌要費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，但鏈霉菌確實有一個計劃。

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，當它準備繁殖時，它會產(chǎn)生孢子，這些孢子可以將新生的細菌傳播到四面八方。

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，通過促進土壤節(jié)肢動物孢子的擴散，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.

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

The research has been published in Nature.

這項研究發(fā)表在《自然》雜志上。