Microbe Week: Paramecium.

If you are a regular biology student, your first encounter with the microbial world will probably be with a slipper-shaped fellow called a Paramecium. It looks vaguely like an elliptical blob with strange hairs along its sides. They are rather bland as far as protists go, but simple and familiar enough to create a solid basis.

They aren't THIS colorful. Usually.

Nonetheless, it makes sense as an intro to protists. K? K.

Paramecia are found in fresh water all over the world with a few species found in the ocean. They are also frequently found in biology labs, often slowed down so that the students can observe them better. They eat yeast, bacteria and algae. Some have symbiotic algae in them already. They can reproduce sexually or asexually, which helps explain why they're so popular.

Cover your eyes, children.

 

A single-celled organism like a paramecium needs to do all the things that any other animal needs to do: move, eat, reproduce, defecate, the works. All cells need to get energy. Paramecia have mouths, organelles (mini-organs), gullets, two nuclei, and a special pump that makes sure that they do not shrivel up or explode via osmosis. Oh, and yes, they do poop. Everybody poops.

Guess what the anal pore does?

Paramecia move by fluttering tiny little hairs called cilia. They move the opposite of whatever direction the hairs are folded - that is, backwards-folding hairs move the paramecium forwards, and forward-folding hairs move the microbe backwards. If you think this sounds topsy-turvy, paramecia really do turn as they move.

Since paramecia are the main protists used in science, quite a few experiments have been done with them. One of the most impressive I have seen is the fishing rod made by Joe Davis, who can also hear the different sounds of microbes. Using a bunch of high-tech gizmos, one can fish for paramecia beneath a microscope. The fishing hook he designed fits perfectly into the oral groove of a paramecium. It really does tug when you've got a big one!

Creature Feature: Malaria.

Malaria is one of those diseases that one only hears about in third world, tropical countries (but used to be more widespread). Most people only know that it is spread by mosquitoes and that it really, really sucks to get because there is no real cure. This is the tropical disease that single-handedly renders nations poor and incapable of economic recovery. It's that bad.

Actually, this is kinda cute.

Oh, and it's a critter. Not a virus, not a bacterium, a single-celled critter commonly called a protist. More accurately, any disease caused by a microscopic organism called a Plasmodium can be called "malaria." There are several Plasmodium species that can infect humans including P. falciparum, P. malariae, P. ovale, P. vivax, and P. knowlesi. P. falciparum is the one that most people are worried about, although any one of the above will at least ruin your year.

While most parasites try to make their presence as innocuous as possible, malaria does not even try. It can incubate for up to a year without any noticeable symptoms, but after that, its presence becomes known very quickly. This is not a friendly parasite; it makes a tapeworm look like a good neighbor.

 
Yeah. Kinda like this in comparison to malaria.

The symptoms of malaria vary slightly from species to species. Common indicators are fever, chills, and headaches. If left untreated, the spleen may also swell (do you know where your spleen is?), and, eventually, the parasites can cross the blood-brain barrier, causing coma and death. Since some  parasites use the liver as part of their life cycle, thorough tests for malaria require both blood and liver examinations.

Malaria starts its life in the gut of an Anopheles mosquito. The mosquito bites an infected human, sucking immature plasmodia into her gut. They mature slightly into sporozoites and travel to her saliva. Then, she is ready to bite and start the cycle again. We realize that one mosquito may well look like the next to most of you, but please be on the lookout for this one:

Once inside a human, the sporozoites (the wormy things from earlier) rupture, releasing countless merozoites. These swiftly infect red blood cells and reproduce asexually within them. P. falciparum goes for the liver before heading towards the blood; when the infected liver cells burst, the malaria then goes for the erythrocytes. In short, these are protozoans that reproduce like a virus.

This might actually make a bitchin' roller coaster.

 

Over time, there have been a number of "cures" for malaria. The first was quinine, a substance originally found in the cichona tree in the Peruvian Andes. Several other drugs, including fakes common in Asia, have since been developed, but Plasmodium protists gain drug resistance just like bacteria and viruses do. They evolved with us and will continue to evolve with us.

We're fucked.



Tomorrow: It looks like a kingsnake, but it swims!