Tuesday, December 11, 2012

Caenorhabditis elegans as a model organism

Figure 1. Image of Caenorhabditis elegans under electron microscopy
In the world of biology, Caenorhabditis elegans is a powerful model organism for the study of human related systems, including neurobiology, developmental biology and genetics. There are a number of reasons that this organism is advantageous for the use in these medically relevant areas of research. A few of these reasons include: its ability for genetic manipulation, its ease of maintenance, its short and prolific life cycle and its similarity between humans (1). These characteristics have also allowed this organism to be used in an increasingly fashion for toxicology research of both drug related studies and also high-throughput screening approaches.

To begin the discussion, we will start with a brief explanation of what a high-throughput screening analysis is. Simply put, it is a machine that has the ability to quickly determine the biological or biochemical activity of a large number of drug-like compounds. For most microbiology majors such as myself, the other terms may be considered to be in our daily vocabulary. However, I assume not everyone has the same basis here. In order for you to understand these concepts, and why C. elegans is such a cool organism, I will go into further detail of these all in a bit.

Though the specifics as to why C. elegans is an important organism is the primary point of this post, it is with the upmost of respect to give credit where credit is deserved. This brings us back to 1963. While in his lab, Dr. Sydney Brenner observed the importance of model organisms for molecular biology; he introduced Caenorhabditis elegans as a “model organism for pursuing developmental biology and neurology” (2). Ever since the introduction of this organism by Dr. Brenner, it has been used around the world in many laboratories and also in many Biological classrooms.

Now that we cleared up who actually discovered C. elegans for the use as a model organism, let’s get back to the basics. What exactly does all of this, “its ability for genetic manipulation, its ease of maintenance, its short and prolific life cycle and its body size,” actually mean? In the realm of biology, more specifically genetics, organisms such as C. elegans can been genetically modified. I know the term genetically modified is controversial to some, but hear me out. If, in the lab we genetically modify an organism, by say, inserting a gene of interest into the genome, we can use various tools to measure the affects that the gene has on the organism. This in turn, allows us to hypothesize what certain genes do in the human body. Pretty important, I would say. When it comes to genetically modifying an organism, some organisms do this with ease. Some on the other hand are a bit more stubborn, shall I say. And, it should be of no surprise that C. elegans is an organism that undergoes genetic modifications with ease.

Instead of boring you with in an in depth analysis of why every aspect of C. elegans is a great model organism, I though I would just cut to the chase, so that we can get into something that is a little more relevant to, say, you or me. It is easy to maintain. And because of this, they are cheap to retain in the lab. In a world so driven by money, of course this is an important component. Also, when discussing an organism that is genetically modified, looking at its offspring is important. Because C. elegans has a short and prolific life cycle, as previously stated, genetic studies can be completed in a timely manner, to see how certain genetic traits are passed down to the offspring. Once again this saves on time, and we all know what we save when we save on time… Money!

These are all important concepts when identifying model organisms, however, none of them are the most important. The underlying reason why C. elegans is so important for the success of the human race is the large amount of homology (scientifically correct) or similarity between humans. Without this similarity, the effects that one particular drug has on C. elegans would like have no relation to how humans would react to the same drug.

So those are all reasons why C. elegans is a good model organism. But, what does this actually do for us? Well, let’s take a look at an important disease that affects an estimated 1 million people in the U.S. and an estimated 6.3 million people worldwide (3).

I’m sure you have all heard of Parkinson’s Disease, in fact I wouldn’t find it surprising that a large percentage of you know someone who has suffered from it. In the off chance you are not familiar with what it actually is, here’s a sneak peak on the disease. It is the degeneration of dopamine (a very important chemical) receptors in the brain. Symptoms begin by simple tremors in a limb. But, after just 2 short years of living with this disease, an individual may have severe stiffness and the tremors will get worse. Eventually, the individual will be unable to care for him or herself.

C. elegans, surprisingly enough contains 8 of these receptors involved in Parkinson’s Disease (1). After obtaining a culture of mutated worms, researchers can treat them with various types of drugs. Because we live in the 21st century, researchers also have the ability to perform pharmacological evaluation of how the mutants are reacting with the drugs. It might not sound interesting to you, but one day C. elegans may be the underlying reason why you are still alive.  

I bet at the beginning of this paper, you were thinking, “Oh, great. Here we go again. Another scientific paper that I am not going to understand.” Well, I hope that is not your final thought. Science is ever evolving and because of that it is important that we all keep up with what is happening. You never know what tomorrow may bring. But, know this, tomorrow we will solve something, somewhere, that will allow us to solve something next day and the next day.

There is much that can be learned form Caenorhabditis elegans. I strongly believe that in the upcoming years, this organism will be used ever more for the investigation of mechanistic roles of certain genes that play a role in diseases such as Parkinson Disease. Due to the ease of its maintenance and storage, and also because of its similarity between humans, this organism will, for many years, be an important component of toxicology and pharmacological research. And, if you are anything like me, you know that anything dealing with pharmacological research can be worth some big money!

If this paper interested you in learning more about C. elegans, or even different organisms that are being used in scientific labs all around the world, here is a great place to start. Enjoy!

1. Leung, M. C. K., Williams, P., Benedetto, A., Au, C., Helmcke, K., Aschner, M., et al. (2008). Caenorhabditis elegans: An emerging model in biomedical and environmental toxicology. Toxicological Sciences, 106(1), 5-28. doi:10.1093/toxsci/kfn121

2. Nass, R., Miller, D. M., &Blakely, R. D. (2001). C. elegans: A novel pharmacogenetic model to study
parkinson's disease. Parkinsonism Related Disorders, 7(3), 185-191. doi:10.1016/S1353-8020(00)00056-0

3. Parkinson's disease health center. (2012). Retrieved November 30, 2012

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