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How do I prepare culture media for protozoans?

Culture media made by soaking or heating fresh or dried organic (usually plant) material in water are known as "infusions." Organic materials used include hay, wheat seed, rice and oat flakes-either individually or in some combination.

The source of the water used is critical. Spring water, well water, and filtered water from unpolluted streams or ponds, are the best choices. The ratio of organic material should be approximately 7 grams (0.25 ounces) per liter.

To pre-treat the organic material, place it in boiling water for one to two minutes, remove it, and maintain it under sterile conditions until it is needed. When you are ready to set up the cultures, pour one inch of water (pre-boiled) into a culture dish (3.5" to 4.5" diameter) and add the organic material. Some specific examples are: Hay/Rice Medium-To the dish of pre-boiled water add two or three grains of rice and three small (2") pieces of timothy hay. Let stand, uncovered, 24 to 48 hours and inoculate. Recommended for all types of amoeba and ciliates.

Wheat Medium-To the dish of pre-boiled water add four to six grains of pre-treated wheat seed and let stand, uncovered, 24 to 48 hours. Inoculate with Blepharisma, all types of Paramecia, Stentor or Vorticella.

For culturing non-specific organisms, prepared infusions can be inoculated with water (a few mL) from any nearby pond, stream or puddle. See what develops!

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