Blepharisma

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Blepharisma is a genus of heterotrich family. ciliates (a type of protista) which contains many species. Its members are elongated and roughly egg-shaped, with a contractile vacuole without collecting channels. Typically, they are pigmented with some shade of red or pink. The anterior pole is bluntly pointed, while the posterior pole is blunted ^[1]. The body is noncontractile, even within the same culture. They are commonly viewed under microscopes in science classes, as they are generally readily available from scientific supply stores.

Reproduction

Blepharisma reproduce by going through the four phases of Binary fission. They also make use of conjugation, unlike some other ciliates. They exchange nuclear products that results in the reshuffling of hereditary characteristics, as in sexual reproduction. Conjugation does not always result in immediate increase in numbers, but often it is immediately followed by binary fission.

A pair of ciliates is less agile than the individuals. They still spin, and in general they move together, but at times they appear to conflict or to attempt to pull in different directions. There is a slower rotation with the pair, but they do move up and down in and out of the focus of the microscope. Finding conjugating pairs is more difficult than finding individuals.

Cilia and Movement

Blepharisma is covered in tiny hairlike parts called cilia, which allows it to move through water - more slowly than vinegar eels, but faster than Volvox. Because of its cilia on all sides, Blepharisma can turn in any direction and often spins around. It spirals as well as spins in a circular motion. It can change direction very easily, which makes it somewhat difficult to keep in view on a microscope. They use their cillia as well as to sweep food into their buccal cavity (mouth).

Feeding

As Blepharisma is a microphagus filter feeder and a ciliate, it is classified in the phylum Ciliophora. It generally eats bacteria from decomposing vegetation, which is drawn into the buccal cavity and then passes to the food vacuoles at the posterior end of the cell.

Appearance

Blepharisma ranges in size from approximately 150 to 300 micrometres.

Blepharisma is particularly notable because of its unusual color. Unlike most protists, they are a faint shade of pink. This is not visible under brightfield illumination.

Behavior

Despite the availability of many still images displaying their structure, there is still little information regarding the behavior and movement of Blepharisma. Still images can provide excellent views of their internal organelles, but video footage is necessary to view their movement. However, as with any small, transparent moving organism there are challenges involved in video recording which have yet to be overcome.

If kept at room temperature Blepharisma moves very quickly, making it difficult to keep it in view by moving the microscope stage. After being placed into a refrigerator for several hours, they slow down notably making them easier to follow. Various substances such as glycerin can be used to suspend or greatly deter motion. However, chilling the specimen is sufficient for viewing their normal movement.

Notes

References

Blepharisma