科学美国人60秒 益生菌可以帮助拯救过热的珊瑚（在线收听）

Probiotics Could Help Save Overheated Coral

益生菌可以帮助拯救过热的珊瑚

Sarah Vitak: This is Scientific American’s 60-Second Science. I’m Sarah Vitak.

Charles Darwin’s famous trip on the HMS Beagle is primarily known for bringing us the concept of evolution. But  Darwin also investigated coral reefs and their formation. One thing about reefs in particular really confused him—that conundrum became known as Darwin’s reef paradox. The paradox is this:

Sarah Vitak：这是科学美国人的 60 秒科学。 我是莎拉·维塔克。

查尔斯达尔文著名的小猎犬号旅行主要是因为给我们带来了进化的概念。 但达尔文也研究了珊瑚礁及其形成。 关于珊瑚礁的一件事让他特别困惑——这个难题被称为达尔文的珊瑚礁悖论。 悖论是这样的：

Voolstra: How can you find this lush, teeming of life in the otherwise, nutrient depleted ocean.

Voolstra：你怎么能在原本营养枯竭的海洋中找到这种郁郁葱葱、充满生机的地方。

Vitak: That’s Dr. Christian Voolstra, a professor at the University of Konstanz in Germany.

Vitak：那是德国康斯坦茨大学教授 Christian Voolstra 博士。

Voolstra: And the trick is symbiosis. Corals are basically sessile organisms or animals, so they basically pick a place and they sit and then they cannot move. So the way they make a living is that they team up with micro algae inside the tissues. And this is essentially tiny plants that do photosynthesis. And this photosynthesis generates sugars. And these sugars will be essentially delivered to the coral animals.

Voolstra：诀窍是共生。 珊瑚基本上是固着的生物或动物，所以它们基本上是找个地方坐下，然后就不能动了。 所以他们谋生的方式是他们与组织内的微藻合作。 这本质上是进行光合作用的微小植物。 这种光合作用会产生糖。 这些糖基本上会被输送给珊瑚动物。

Vitak: These little critters across the globe are in great peril a lot of danger. According to a report from the Global Coral Reef Monitoring Network published in October 2021, we lost 14% of the world’s coral reefs in the last decade. This was mostly due to large scale bleaching events. Coral bleaching is triggered by changes in the coral's environment—including increased temperature, sunlight, or pollutants. But what exactly does it mean for coral to be bleached?

Vitak：这些遍布全球的小动物正处于极大的危险之中。 根据全球珊瑚礁监测网络 2021 年 10 月发布的一份报告，在过去十年中，我们失去了 14% 的世界珊瑚礁。 这主要是由于大规模的漂白事件。 珊瑚白化是由珊瑚环境的变化引发的——包括温度升高、阳光或污染物。 但珊瑚被漂白究竟意味着什么？

Voolstra: The color of corals comes from the photosynthetic pigments of the algae. So the minute these algae are out, the coral looks white. So what happens in bleaching is that these symbiotic algae or tiny plant cells are getting expelled out of the coral tissue.

Voolstra：珊瑚的颜色来自藻类的光合色素。 所以当这些藻类出来的那一刻，珊瑚看起来是白色的。 所以漂白过程中发生的事情是这些共生藻类或微小的植物细胞被驱逐出珊瑚组织。

If the environmental conditions actually become better again, they can actually take up their algae again and they are fine. So this is a transitory state. But In actuality, if the environmental conditions persist, the coral literally starves to death.

如果环境条件真的再次变好，它们实际上可以再次吸收它们的藻类并且它们很好。 所以这是一个暂时的状态。 但实际上，如果环境条件持续存在，珊瑚就会饿死。

Vitak: Dr. Voolstra and his team were really interested in research that took a new approach to helping coral cope with increased ocean temperatures: treating them with probiotics. [Christian R. Voolstra et al., Extending the natural adaptive capacity of coral holobionts]

Vitak：Voolstra 博士和他的团队对采用新方法帮助珊瑚应对海洋温度升高的研究非常感兴趣：用益生菌治疗它们。

Voolstra: The general consumer knows that you can buy yogurt with probiotic cultures, right? There are some bacteria that are good for your gut.

Voolstra：一般消费者都知道你可以买到益生菌的酸奶，对吧？ 有些细菌对你的肠道有益。

Vitak: Just like humans, coral have a microbiome; a community of microorganisms that live on or inside them. Previous work had shown that bolstering the coral’s bacterial microbiome by giving them doses of probiotics helped them survive challenging conditions. The process is similar to how we work with microbiomes and probiotics in people.

Vitak：就像人类一样，珊瑚也有微生物群落； 生活在它们上面或内部的微生物群落。 以前的工作表明，通过给珊瑚提供一定剂量的益生菌来增强珊瑚的细菌微生物群，可以帮助它们在充满挑战的条件下生存。 该过程类似于我们在人体中使用微生物组和益生菌的方式。

Voolstra: You extract microbes from these very resilient individuals, and then you literally transplant them or offer them to less resilient individuals of the same coral species. So it's not that you're putting something there that wasn't there, but it's really like this human fecal transplants. You have a healthy donor, and you offer these bacteria to an affected recipient.

Voolstra：你从这些非常有弹性的个体中提取微生物，然后将它们移植或将它们提供给相同珊瑚物种中弹性较差的个体。 所以不是说你放了一些不存在的东西，而是真的就像人类粪便移植一样。 您有一个健康的捐赠者，您将这些细菌提供给受影响的接受者。

Vitak: This had already been shown as a proof of concept in previous research. But Dr. Voolstra and his team wanted to drill down and understand it a bit better.

Vitak：这在之前的研究中已经被证明是一个概念证明。 但 Voolstra 博士和他的团队想要深入研究并更好地理解它。

To do the experiment, they worked in what they call “mesochosms”—sort of a sweet spot between a sterile isolated lab setting and a totally wild reef setting. Basically, they had aquariums with multiple types of corals and some other critters. This allowed them to control conditions but also get a slightly more real-world result.

为了进行这项实验，他们在他们所谓的“中观”中工作——这是一个介于无菌隔离实验室环境和完全野生珊瑚礁环境之间的最佳位置。 基本上，他们的水族馆里有多种珊瑚和其他一些小动物。 这使他们能够控制条件，但也可以获得更真实的结果。

One very convenient thing about working with coral is that they are colonial organisms.

Voolstra: Which means that they consist of repetition of the same building blocks. From one colony, you can generate many, many fragments or pieces that all have the exact same genotype with this exact same environmental history. And then you can put them into different conditions.

与珊瑚一起工作的一件非常方便的事情是它们是殖民地生物。

Voolstra：这意味着它们由相同构建块的重复组成。 从一个菌落中，您可以生成许多片段或片段，它们都具有完全相同的基因型和完全相同的环境历史。 然后你可以将它们置于不同的条件下。

Vitak: Once they had their fragments they treated some of them with a mixture of bacteria that they had carefully isolated, selected, and grown from resilient coral—and, of course, they wanted to have a control for their experiment as well,  so they gave some a placebo saline solution.

维塔克：一旦他们拿到了碎片，他们就会用一种细菌混合物对其中的一些进行处理，这些细菌是他们从有弹性的珊瑚中精心分离、选择和培育出来的——当然，他们也希望对他们的实验进行控制，所以他们 给了一些安慰剂盐水溶液。

Finally, they slowly cranked up the heat to simulate ocean warming.

Voolstra: And this was a very long experiment that essentially lasted over 75 days.

Vitak: What they found was fascinating. All the coral showed signs of bleaching as the temperature increased, but the coral treated with probiotics recovered faster. And they were 40% more likely to survive.

最后，他们慢慢提高热量以模拟海洋变暖。

Voolstra：这是一个非常长的实验，基本上持续了 75 天以上。

Vitak：他们发现的东西很吸引人。 随着温度的升高，所有的珊瑚都出现了白化的迹象，但用益生菌处理的珊瑚恢复得更快。 他们生存的可能性增加了 40%。

Voolstra: Okay, like as a coral biologist, or as a biologist, in general, I think you're usually very happy if you have a 5% effect or something observable that you can count with reasonable numbers. This is massive. I mean, if you almost double the survivorship, this is huge.

Vitak: The team also looked at how  adding this probiotic cocktail changed the coral’s microbiome and—how it changed the coral itself. Adding the probiotic changed the composition of the coral’s microbiome.

Voolstra：好的，就像作为珊瑚生物学家，或者作为生物学家，一般来说，我认为如果你有 5% 的影响或可以用合理数字计算的可观察到的东西，你通常会很高兴。 这是巨大的。 我的意思是，如果你的存活率几乎翻倍，这是巨大的。

Vitak：团队还研究了添加这种益生菌混合物如何改变珊瑚的微生物组，以及它如何改变珊瑚本身。 添加益生菌改变了珊瑚微生物组的组成。

Voolstra: It also instigated a change in the expression of certain genes in the coral host. And those genes, were really kind of the go-to genes that you would bet on if this is for increased recovery.

Voolstra：它还引发了珊瑚宿主中某些基因表达的变化。 而那些基因，如果这是为了增加恢复，真的是你会打赌的首选基因。

Vitak: So basically—things like repair genes, immunity genes, and stress response genes.

Voolstra:  So this is kind of the cliffhanger of this study, you actually change stuff in the host. And in the correlate host, and we don't know how long these changes will stay on. Of course, if those changes can be kept long term, you would not need to keep this probiotic treatment going on and on, right?

Vitak：所以基本上——比如修复基因、免疫基因和压力反应基因。

Voolstra：所以这是这项研究的悬念，你实际上改变了主机中的东西。 在相关主机中，我们不知道这些变化会持续多久。 当然，如果这些变化可以长期保持，你就不需要继续这种益生菌治疗了，对吧？

Vitak: Which would be amazing in terms of translating this to the real world.

Voolstra: I mean, there’s 300,000 square kilometers of coral reef. There's billions of coral. So if you want to bring a little magic potion underwater and inoculate each coral, this becomes unmanageable. No organism makes a living in isolation. And I think we're just getting better at understanding this.

Vitak：在将其转化为现实世界方面，这将是惊人的。

Voolstra：我的意思是，有 300,000 平方公里的珊瑚礁。 有数十亿珊瑚。 所以如果你想在水下带上一点魔法药水给每一个珊瑚接种，这就变得难以管理了。 没有有机体以孤立的方式谋生。 我认为我们在理解这一点方面做得越来越好。

Vitak: Thanks for listening. For Scientific American’s 60 Second Science, I’m Sarah Vitak.

维塔克：感谢您的收听。 对于《科学美国人》的 60 秒科学，我是 Sarah Vitak。