Positive About Protozoa

What are Protozoa?

Present in nearly every environment, these are mostly microscopic organisms, found alongside algae and slime moulds, in the kingdom Protista, the place to find all the oddities that don’t belong to the animal, plant or fungi kingdoms.

Protist organisms are mostly unicellular (exceptions include slime moulds and seaweeds).

The protist kingdom is one of the most diverse, but all inhabitants share one important trait: eukaryotic cells, the basis of all advanced life on earth, which also makes them one of the most ancient of kingdoms. Many can photosynthesise, some can live without oxygen, and they are all important in our ecosystems as a fundamental part of the food chain as well as decomposing material, aiding the major biogeochemical cycles of life. They continue to evolve as environments change, becoming prevalent in every environmental niche

Protist cells have a nucleus and membrane bound organelles that you would see in animal cells. They mostly reproduce asexually and can move using various methods including cilia (motile ‘hairs’), flagella (motile ‘tail’) and pseudopodia (temporary extensions of the cytoplasm).

Why are they useful in schools?

Protozoa, being more complex than they are basic, are very easy to study under the microscope, generally looking at feeding, reproduction and motility. Some are described below:

Amoeba Proteus

Amoeba have no definite shape, ranging in size from 2-3um to up to 20cm, and move using pseudopodia: temporary extensions of the cytoplasm, often called false feet. This is where the term ‘amoeboid movement’ comes from. Parasitic amoeba have been found in humans and can cause dysentery among other diseases (we don’t sell those ones!). They are aquatic organisms, and if conditions become unfavourable to them, they will transform into a ‘microbial cyst’: a protective ball that will help them survive until better conditions return.

Euglina Gracilis

Euglina are photosynthetic flagellated protozoa, found in fresh, sea and marsh water. They possess an eyespot (or stigma), a specialised structure of photoreceptors and pigments that can detect and react to changes in light levels. Parasitic forms of Euglina exist which cause diseases such as Leishmaniasis and African sleeping sickness, but don’t worry, we don’t sell those either!

Paramecium Caudatum

Paramecium can live for thousands of years in aquatic environments, they are ciliated protozoans, having hairlike structures all around the ‘body’ which move in a wave like fashion, propelling the paramecium around. The cilia can move in either direction, allowing the paramecium to reverse away from objects in its path, however the wave like motion of the cilia does cause the paramecium to move in a spiral fashion. Some of the cilia are specialised into prey catchers, being longer and found at the end of the organism. Paramecia are not photosynthetic, so have no green chloroplasts, and respire using oxygen which diffuses across the cell membrane. Paramecia have not been found to cause disease in humans, and they are important decomposers in the ecosystem.

What do we sell

Here at Breckland Scientific, we currently sell 3 types of Protozoa, in 30ml cultures (suitable for up to 30 students).

Amoeba Proteus - A very large and vigorous strain which displays protoplasmic streaming (cyclosis), prey encapsulation and phagocytosis (engulfing prey to ingest them). An excellent textbook species for demonstrating pseudopodia and amoebae morphology.

Euglina Gracilis - A typical green phytoflagellate for illustrating flagellate motility and photoautotrophic nutrition. The distinct eyespot (stigma) stimulates the cells phototactic response towards moderate light intensity.

Paramecium Caudatum - The 'slipper animalcule' named after the resemblance of its pellicle to the shape of a slipper. Probably the most popular textbook species for illustrating ciliate morphology and behavioural traits. Although the organism is highly motile our cultures often contain sufficiently dense populations for continual observation under the microscope.

Mixed Protozoa (50ml) - A jar of mixed curricula protozoa, including Amoeba, Paramecium, Euglena, Stentor, Blepharisma, Vorticella and Euplotes, etc. The culture provides a visually exciting introduction to the diversity of the ciliates, flagellates and amoebae.

When you receive your live protozoan culture, open the lid of the jar to allow oxygen to enter. You can (gently) aerate the culture using a clean pipette.

Cultures will last up to a week in the jar, but you can grow them on using a specialised medium with a food source for the protozoa. For more information on culturing protozoa go to our website.

Shop Today