So two weeks ago we looked at an aquatic salamander that had the incredible ability to regenerate lost limbs and even other parts of its body. This week we will be taking a look at another aquatic animal, but this one chooses to make its home among the salty ocean waves rather than the tranquil freshwater lakes that the Axolotl loved.
This Jellyfish’s Life is Crystal Clear
The Crystal jellyfish (Aequorea victoria) makes its home in the ocean waters along the coast of the Northwest United States and has a rather important role to modern biological science. But before I delve into the explanation of this organisms’ importance to science, let’s take some time to learn about it first.
As I stated before, this animal is a jellyfish and is found in the ocean waters along the coast of California all the way north to British Columbia, Canada. These little jellyfish range from 3-10 inches in diameter and comes, like most jellyfish, with a set of stinging tentacles. These tentacles are used to paralyze and capture its prey, which include copepods (small crustaceans), plankton and other kinds of jellyfish. If you know anything about jellyfish, then this is all fairly standard. So what is it about the Crystal Jellyfish that sets it apart and makes it helpful to scientists? Well, it has to do with a little thing called bioluminescence.
I know that bioluminescence is a big word, but essentially all it means is that the organism can produce its own light. Think of the fireflies that you might see in the summertime; the yellow-green light that they produce is an example of bioluminescence. The Crystal Jellyfish produces two kinds of light, blue light and green light, which are created by an intricate reaction between Calcium ions, and two proteins called aequorin and green fluorescent protein (GFP).
When the jellyfish releases stored calcium ions, these ions bind to the aequorin protein which then causes it to produce a blue light. The blue light produced by the aequorin protein then activates the green fluorescent protein, which then produces a bright green light. Crudely, you can think of it along the lines of a glow-in-the-dark ball. In order to get the ball to glow green, you first need to shine a light on it, much like how the green light isn’t produced in the jellyfish until a blue light hits the protein.
In the short video below, you can see both the blue and the green light produced by the jellyfish. The blue light is emitted from the majority of the jellyfish’s body while the green light only appears around the rim.
The bioluminescence is activated when the jellyfish are in stressful situations, serving as an anti-predator defense. Perhaps the bright colors scare away most predators or at the very least confuse them long enough for the jellyfish to disappear into the ocean depths. It is this green fluorescent protein- GFP for short- that scientists have adapted for use in biochemical, cellular and genetics research.
GFP and its Applications
GFP is used as a biological tracker or highlighter in a cell. Essentially, scientists attach the gene for GFP to the end of a gene in a cell that codes for a protein they are interested in. The GFP will follow the protein of interest through the cell or organism and by fluorescing the GFP, scientists can identify where the protein travels.
For example, let’s say that a scientist attaches the GFP gene to the end of a gene that makes a protein which is a part of the cellular membrane. When the gene creates the cellular membrane protein, the GFP will also be made and will be attached to the membrane protein. Therefore, scientists can then shine a blue light on the cell which causes the GFP to fluoresce, thus revealing the outline and location of the cell membrane.
While this may seem like a very abstract discovery, the implementation of GFP and now it’s many variously colored derivatives has led to an indescribable expansion of the limits of the scientific research. One study states that “the green fluorescent protein (GFP) from the jellyfish Aequorea victoria has vaulted from obscurity to become one of the most widely studied and exploited proteins in biochemistry and cell biology.” That study was from 1998, only 3 years after its first use in a scientific experiment. Since then GFP has been used for such things as:
- Tracking protein movements within cells
- Creating fluorescent plants and research animals
- Understanding the differences between cancer cells and normal cells
- Creating images of cellular and tissue structures
The GFP has been so vital to modern biochemical research that in 2008, the Nobel Prize for Chemistry was awarded to Dr. Osamu Shimomura, Dr. Martin Chalfie and Dr. Robert Tsien, the three scientists who first discovered and isolated the protein from the Crystal Jellyfish.
So, jellyfish are much more than lean, mean stinging machines. They have provided us with one of the most important biological compounds to research in recent years and opened new avenues for scientific exploration.