Life at the Edge

Yes, life at the edge CAN be risky…. But not for extremophiles! Not only are extremophiles perfectly suited for their environments, they help us a lot more than you might think. Scientists can learn a lot from studying extremophiles and how they have adapted.

Life first appeared on Earth about 4 billion years ago. Back then, Earth was hotter, had very little oxygen, toxic oceans and hardly any protection from UV rays. The whole Earth was like an extreme environment. Could we have survived there? No, but some organisms were able to.

As Earth became more like we know it to be now, the extreme environments shrank. Scientists believe that some of earth’s first living organisms are very similar to the extremophiles we find today. They had to scatter and there are fewer of them as our environment has changed.

Now, let’s take a look at some specific types of extremophiles. We will start with thermophiles, which are “heat-loving” organisms (usually bacteria). They live in thermal pools at temperatures up to 176 degrees Fahrenheit (80 degrees Celsius).

How can thermophiles survive at such temperatures? And why can’t we? Well, some thermophiles have a special set of proteins called HSP’s (heat shock proteins) that protect them from heat damage. We have them, too, but only produce them when we are overheated. Thermophiles make them all of the time.

Other thermophiles have a special enzyme called a “thermo-zyne” which works best at high temperatures. (Enzymes are special proteins that speed up chemical reactions that help to carry out body functions.) One of these thermo-zynes is called Taq polymerase.

Taq polymerase can be used by scientists to take a small sample of DNA and turn it into a sample large enough to identify. This can be used in crime labs to match DNA samples with suspects…even if only a tiny speck of DNA was left behind.

While we are on the topic of temperature, let’s discuss psychrophiles (organisms that love the cold). Not only do they love the cold, they can’t live without it. They’d die at room temperature.

Organisms that live in the Arctic or Antarctic regions must survive very cold temperatures. The winter flounder, shown below, lives in water that is 28 degrees Fahrenheit (-2 degrees Celsius). That’s below the freezing point of their blood!

So just how do organisms manage to survive in such a cold environment? Polar fish produce antifreeze proteins (AFPs) that lower the freezing point of its blood by a couple of degrees.

There are different types of AFPs, but all of them have possible applications to various fields of science and technology. For example, they could be inserted into plants to help them survive the winter. And they could be put into ice cream to prevent ice crystals from forming and keeping it creamier for a longer time. (Good idea!)