保護與存活：飢餓的細菌不吃蜘蛛絲，何以如此？_風聞

【來源龍騰網】

正文原創翻譯：

Tougher than any fibre made by humans and extraordinarily good at transmitting vibrations to the predators that weave it, spider silk has been a source of inspiration for the development of everything from scaffolding for regenerating bones to bulletproof vests, remote sensors and noise reducers.

蜘蛛絲比任何人造纖維都更加強韌，並能很好地將振動傳遞給織網的捕食者。其成為了許多事物發展的靈感來源：從再生骨頭的支架到防彈背心、遙感器和降噪設備。

Yet one of its most remarkable attributes, its resistance to decay, has received little attention. Some researchers speculate that spider silk keeps hungry bacteria at bay by being laced with antibiotics.

然而蜘蛛絲最奇特的特徵之一——抗腐蝕，卻未被重視。一些研究人士推測飢餓的細菌不腐蝕蜘蛛絲是因為其中含有抗生素。

But work by Wang Pi-Han and Tso I-Min at Tunghai University, in Taiwan, published in the Journal of Experimental Biology, suggests this is not the case.

但台灣東海大學的汪碧涵和卓逸民發表於《實驗生物學期刊》上的文章表明事實並非如此。

Rather, silk manages to avoid being eaten by locking the nutrients it contains behind an impenetrable barrier. Spider silk is made of proteins that ought to be attractive to microbes.

相反，蜘蛛絲將所含營養鎖在無法穿透的屏障內，以此避免被細菌腐蝕。蜘蛛絲是由微生物喜愛的蛋白質構成的。

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Moreover, because webs are often built in environments, like forests and bogs, that are rife with these bugs, there should be ample opportunities for bacteria to settle on the strands and feast. Remarkably, This does not seem to happen.

另外，因為蜘蛛網常常生長於森林沼澤這樣充滿蟲子的環境，所以細菌有充足的機會棲居其上、盡情飽餐。令人驚異的是，這一切似乎並未發生。

Dr Wang and Dr Tso were curious about how spiders manage this. They began their investigation by putting bacteria and spider silks together in laboratory conditions perfect for bacterial growth. They worked with silk strands collected from three species of spider that build their webs in different environments, and set these down on nutrient-rich plates. Each plate had one of four bacterial species growing on it.

這是如何實現的？王博士和陶博士感到十分好奇。他們對此展開了研究，將細菌和蜘蛛絲放在一起，置於適宜細菌生長的實驗室條件下。從在不同環境中織網的三種蜘蛛處收集了蜘蛛絲，將它們放進富含營養的培養皿中。共四種細菌，每個培養皿中都有一種細菌在蜘蛛絲上生長。

The team then used microscopes to monitor the behaviour of the bacteria over the course of 24 hours. After repeating the experiment three times, they found that the bacteria never fed on the silks.

之後這個團隊用顯微鏡觀察24小時內細菌的行為。在重複該實驗三次之後，它們發現細菌從未腐蝕蜘蛛絲。

They also found, however, that the strands were not immune to having bacteria grow over and around them—suggesting that those strands were not laced with antibiotics.

然而，它們也發現細菌在蜘蛛絲上和其周圍得以生長，表明蜘蛛絲內並無抗生素。

The two researchers then tried growing their bacteria directly on silk strands, by providing them with a range of nutrient supplements.

其後，兩位研究員為蜘蛛絲提供了一些營養補充劑，嘗試着直接讓細菌生長在蜘蛛絲上。

Only one of these supplements, nitrogen, encouraged consumption of the silk.

只有一種補充劑——氮——讓細菌以蜘蛛絲為食。

When the strands were lathered in a nitrogen-rich solution, bacteria ate them. Without nitrogen, they were held at bay.

當蜘蛛絲被塗上富含氮的溶液時，細菌便以蜘蛛絲為食。如果沒有氮，細菌就不吃。

This is odd, because proteins (of which silk is made) are, themselves, rich in nitrogen. That led Dr Wang and Dr Tso to conclude that the antibacterial properties of spider silk are caused not by any sort of antibiotic but, rather, the structure of the silk itself.

這很奇怪。因為構成蜘蛛絲的蛋白質自身就富含氮。王博士和陶博士於是得出結論，蜘蛛絲的抗菌特性並不是因為其中含有抗生素，而是由於蜘蛛絲自身的結構。

Natural sextion, it seems, has driven spider silk to store the proteins it is composed of behind a layer made impenetrable by its physical rather than its chemical structure.

自然選擇似乎驅使蜘蛛絲將構成自身的蛋白質儲存於一個表層之後，因其物理結構而非化學結構而無法穿透。

What, exactly, that structure is the two researchers have yet to determine. Once it has been elucidated, though, the discovery should pave the way for artificial antibacterial materials that do not use antibiotics to keep the bugs away.

這一結構具體是什麼，兩位研究人員還沒有定論。但是，一旦將其闡明，這一發現將會為人造抗菌物質鋪平道路，不必使用抗生素就可以使細菌遠離。

譯者補充：

1. 所提論文見於《實驗生物學雜誌》2019年10月23日，222卷，20期。論文題目為Nitrogen inaccessibility protects spider silk from bacterial growth。doi: 10.1242/jeb.214981

2. 汪碧涵教授郵箱：[email protected]；卓逸民教授郵箱：[email protected]。