Category Archives: Animals

Botox is my frenemy

Pufferfish, scorpions and black mamba snakes, oh my! These cuddly critters all make toxins affecting the cell membranes of nerve cells. If you haven’t read my last two posts, “Don’t eat pufferfish” and “Your potassium channel,” now would be the time. I’m experimenting here with a three-part series and this post is the last of the three.

Toxins affecting nerve cells, like those produced by pufferfish, scorpions and snakes, are called neurotoxins. Although tetrodotoxin (this is the toxin from pufferfish) is somewhat commonly known, I’m guessing the most prominent neurotoxin is Botox.

Toxin? Yep. Botox is the botulinum toxin. It comes from the Clostridium botulinum bacteria and ranks with tetrodotoxin as one of the most toxic substances out there.

The botulinum toxin has become popular in the medical world because of its ability to paralyze cells. It’s used in minute amounts for cosmetic treatment.

Load up on Botox before a poker game!

Last year the U.S. Food and Drug Administration (FDA) approved Botox shots for treatment of chronic migraine condition. Here’s a NY Times article about the FDA approval.

I’m inserting my opinion into this paragraph before I return to the science of Botox. I have mixed feelings about Botox treatment: it’s my frenemy. I am a migraine sufferer, and thus very well understand the plight of chronic migraine sufferers.

I sometimes have luck with pharmaceuticals (i.e. prescribed drugs) and sometimes do not. The appeal of a Botox shot to curb a persistent, debilitating migraine is, thus, not lost upon me. However, Botox is a toxin, and if given incorrectly, could paralyze me. However, here’s a NY Times article from 2009 (pre-FDA approval) that makes me want to try Botox. FRENEMY!

Here’s how Botox works. Let’s say I go to the doctor complaining of a wrinkle in my forehead. The doctor injects a tiny amount of Botox directly into my forehead. She aims to hit the weak muscle underneath my wrinkle. (If the muscle weren’t weak, there would be no wrinkle!)

The toxin, once inside my body, travels to the nerve cell responsible for controlling the weakened muscle. The toxin plugs that nerve cell’s sodium channel. This prevents the nerve cell from talking to its neighbors.

Sound familiar? This is exactly how tetrodotoxin works.

As a result, the cell loses its ability to function. No longer controlled by a functional nerve cell, the muscle relaxes and my wrinkle disappears.

This procedure is an art form. Too little toxin and the wrinkle stays. Too much toxin and we have a repeat performance of what happens from eating pufferfish.

But not all toxins are neurotoxins. In the plant kingdom a toxin works differently.

The black walnut tree produces the drug-like toxin juglone. Juglone is made in the tree’s roots, bark and leaves. Juglone acts as an herbicide to nearby plants. The toxic zone is expansive, extending 50 feet from the base of the tree in every direction.

This is a black walnut tree. Toxic things are soooo pretty! Source: http://www.tree-pictures.com

The juglone toxin wipes out everything in its path. It hits alfalfa plants, tomato plants, apple trees, and [insert your favorite plant or tree]. The attacked plants and trees wilt, and their leaves darken and wither away. The black walnut tree can now eat like a king: it has no competition.

Toxins are carried in a liquid form, either as venom or poison.

If an animal is venomous, the animal will inject venom directly into its prey by biting or stinging.

If an animal is poisonous, the toxin is harmful only if we touch it or eat it or inject it ourselves.

    The pufferfish? It’s poisonous. It’s not going to bite us; we have to touch it or eat it.

    A scorpion? It’s venomous. It’s sure as heck going to sting us.

    The black mamba snake? Venomous. Bite away, snake.

    The botulinum bacteria? Poisonous. Ever seen a bacterial cell with teeth? Nope. And no, Dad, Pac-Man does not count.

    CHOMP CHOMP CHOMP. I am good at draw-ring.

    The black walnut tree’s toxin juglone? Is that poison or venom? Post a comment with your answer!

For those animals that are venomous, mostly scorpions and snakes, our medical advances provide us with anti-venom. The anti-venom protects us from the toxic effects of the venom, and we can avoid getting sick.

What is anti-venom? It’s an antibody to the venom, thanks to the use of research animals. Researchers inject animals, often horses, with venom that harms humans (but not horses). The horse’s body mounts an immune response to the venom, producing antibodies.

Medical researchers then collect the horse’s blood, isolate the antibodies, and voila – anti-venom.

The anti-venom will help snake and scorpion bites. It’s useless against the pufferfish toxin. Don’t. eat. pufferfish.

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Don’t eat pufferfish

Nature is chock full of toxins. Toxins come from all five kingdoms of life — bacteria, fungi, protists, plants and animals. Although the toxins span a broad range of shapes, sizes, and potencies, they’re all produced for the same reason: warfare.

Toxins come in two main flavors: as proteins and as small organic molecules. The protein toxins are both big and small. The small organic molecule toxins are very small.

What’s a small organic molecule? You probably know it as a (prescription) drug. Check out the image below:

A dizzying array of small organic molecules.

This image is a compilation of pills your doctor prescribes to treat a variety of ailments. Inside each colorful little package is one type of small organic molecule.

So a toxin can take drug form or protein form, both of which can enter your body and reek havoc.

The tropical pufferfish, especially prevalent in Japan, carries a small organic molecule toxin — the very small drug kind.

Here’s an adorable, cuddly pufferfish:

Source: Steven Hunt/Getty Images

The drug-like toxin found in pufferfish is called tetrodotoxin. An interesting little technicality is: the pufferfish itself does not make the toxin, but rather bacteria living inside the pufferfish produce it!

Tetrodotoxin is one of the most potent toxins out there. If you eat the equivalent of a grain of salt, you’re a goner. One tenth of that has the same result. One hundredth of that: same result.

Tetrodotoxin affects a cell’s sodium channel. If you haven’t read my last post, “Your potassium channel,” now would be the time.

The sodium channel has the same functionality as the potassium channel. The difference is only the type of stuff the channel flushes out and takes in. For a potassium channel, the type of stuff is potassium. For a sodium channel, the type of stuff is sodium.

We’ve learned that we don’t want to mess with these channels, because messing with the channels inhibits the cells from communicating with each other. And, just like with potassium, cells use sodium to talk. For example:

    Cell 1: “Hey, did you see the latest episode of ‘Glee?’”
    Cell 2: “Yeah, those New Horizons kids totally nailed it!”

I jest. Cells don’t talk about “Glee.” (Although they should.)

Most toxins affect the cells of the nervous system. So the type of cell that’s of interest here is the nerve cell. On a normal day, the nerve cell opens and closes its sodium channel, flushing out sodium, taking in sodium, all the while transmitting electrical signals to its neighbor cells.

Let’s say I have a hankering for pufferfish. I eat one. I now have tetrodotoxin loose inside my body. The very, very tiny tetrodotoxin finds its way to the sodium channels in my nerve cells.

A tetrodotoxin molecule plops itself down in a channel’s opening. That channel can no longer open or close. The sodium inside the cell cannot get out. The sodium outside the cell cannot get in.

Now that poor nerve cell can’t communicate; it has lost its ability to regulate itself. It dies. The cells around it die, too. Soon, enough cells have died that I’m paralyzed. Oops.

Another toxin that plugs a cell’s sodium channel is called batrachotoxin. This drug-like toxin is produced by the poison dart frog. How cute is this little guy?

A yellow poison dart frog. More than a hundred kinds exist -- all beautiful. Click the frog to learn more.

Besides sodium channel toxins, nature has potassium and calcium channel toxins, too. Scorpions, for example, produce protein toxins targeting the potassium channel of a nerve cell. Whew. I’d hate for the poor sodium channel to be singled out for destruction.

The black mamba snake, the largest venomous snake in Africa, produces a large protein toxin called calciseptine. Calciseptine targets the calcium channel, as you may have guessed from its similar name. This particular toxin is such effective warfare that the black mamba snake eats like a king.

Here’s a black mamba snake eating some unfortunate rodent:

Yummy! Click on me!

Don’t eat black mamba snakes. Also, don’t eat scorpions. Also, don’t. eat. pufferfish.

Glowing jellyfish

Jellyfish glow. It’s true and it’s all because of one protein.

glowing-jellyfish

Source: http://news.nationalgeographic.com/news/2009/05/photogalleries/glowing-animal-pictures/index.html

A protein is a string of amino acids. Imagine a string of pearls, each pearl linked to the next in linear succession to form a beautiful necklace. The pearls are the building blocks for the necklace. Amino acids are the building blocks for a protein. If you string a few together you get a peptide; if you string a lot together you get a protein.

As a long string, free and loose, the protein isn’t doing much and certainly isn’t focusing on its chores. Sorry mom and dad. It needs to assume a particular shape in order to do any work. Free and loose it is essentially useless to the cell, but folded up and tightly bound it is ready for action.

What action? Depends on the protein. They fall into several categories, some quite distinctly and some hosting multiple labels. Much like music, really. Gustav Holst’s The Planets is unmistakably classical. Indigo Girls, however, could be considered rock, Indie, folk, and alternative. In music language, some proteins are strictly classical while others dabble in rock, Indie and folk.

In science language, some transport cargo – the hemoglobin protein carries oxygen, some are hormones like insulin, some are enzymes like monoamine oxidase (inhibitors of which are widespread in the pharmaceutical industry), some provide structure like keratin in hair or collagen in skin and muscles.
types of proteins Source: http://publications.nigms.nih.gov/structlife/chapter1.html

One kind of protein has a really cool job. Its job is to be fluorescent. Shine the right kind of light onto the protein and you’ve got yourself a glowing organism. Whatever your favorite color, there’s almost guaranteed a fluorescent protein for you.

The Nobel Prize for Chemistry in 2008 went out to Roger Tsien of UC San Diego, Martin Chalfie of Columbia University and Osamu Shimomura of Japan for the development of these fluorescent proteins. This work has led not only to a sizable color wheel but also a variety of glowing organisms. Monkey? Glows green. Mice? Green. Worm? Green. Cat? Glows red. Dog? Red. Fish? Green, red AND yellow.

The original source of the green fluorescent protein? Aequorea victoria. Also known as the jellyfish.