HELP!!!! I am doing an experiment on the effect of caffeine on euglena's ability to form cysts.?

Question

Euglena is single-celled protist that can act as an animal or a plant but usually photosynthesizes. in my project i am adding caff to euglena. caff will probably cause euglena to CONTRACT. Recently i learned that caff can also cause euglena to form a cyst to protect itself if there was so much caff. Is CONTRACTING EUGLENA the same thing as CYSTED EUGLENA? b/c when i look@ pix it shows the same thing: euglena in a very round shape (euglena is usually elongated) WHAT IS THE DIFF? is 1 just a contration euglena forms in its euglenoid movemnet & 1 actually is like a shield? my caff in ea. is 5mg, 10mg, and 16 mg. I will observe it under a microspoe and to test my hypothesis (more caff=more cysts or contracted forms) and i will count out of total euglena how many are in normal shape and how many are in constant contracted/cyst form. if u have info against/for my hypothesis please share. and I Still Need Tips on CAre for Euglena. Nutrients they need? they arnt alwys in light...THANKS:)

Answer 1

Different species of Euglena react a little differently to changing conditions. I do not have web sites but rather some experience with several species.

Contraction is a reaction to stress. The idea is to limit the surface area (become more like a sphere). Many chemicals and even physical conditions can cause contraction. Try putting a few (otherwise normal specimens) in the refrigerator to see pure contraction.

The the stress is long term, the individual will become dormant. The shape is usually contracted, but in addition the cell wall is modified. This is the cyst form. You can actually see the wall thickening under a microscope.

Your hypothesis and test seems sound. Have you thought about a pure deionized water comparison?

There is not much to the care and feeding of Euglena. I have raised some with pure water and a pinch of plant fertilizer (Miracle Grow) in strong light. This works well. I used a small fish tank with a grow lamp. A goldfish bowl will work. Wild algae will compete.

You can lessen the wild algae by using water with a few grains of cooked brown rice added. There is not much minerals for the algae, but the rice seems to contain everything that the Euglena need.

I have also used mud-puddle water and "fed" them ground up goldfish food flakes. This with mixed results.

Keeping the water warm, but not hot helps reproduction.

Answer 2

You killed the Euglena when you put them in distilled water (read about osmosis.)