Encystment – protozoan, Biology

Encystment – Protozoan

Encystment is characteristic of the life cycle of many protozoan. The protozoan secretes a thickened envelope (cyst) around itself and becomes inactive with almost a complete shutdown of metabolic activity. This protective cyst is resistant to either desiccation or low temperatures and enables the animal to pass through unfavorable environmental conditions like food deficiency, desiccation, decreased oxygen concentration, pH, etc.

Reproductive phases such as fission, budding and syngamy may occur inside the cysts of some species Encystment is however, not found or is very rare in marine species. Protozoa may be dispersed long distances in either the motile or encysted stages. Water currents, wind, mud, debris, the bodies of birds and animals are common agents of dispersal.

Cysts of some soil inhabiting and freshwater protozoa show amazing durability. The soil ciliate Colpoda has been known to survive in dried soil for up to 38 years On the other hand not all cysts are as durable. Cysts of Entamoeba histolytica can tolerate the acidic medium of the stomach but do not survive desiccation, temperature above 50°C or sunlight. A return of favorable conditions initiates excystment (escape from cysts) in those protozoa in which the cysts are a resistant stage.

Posted Date: 1/12/2013 6:26:27 AM | Location : United States

Related Discussions:- Encystment – protozoan, Assignment Help, Ask Question on Encystment – protozoan, Get Answer, Expert's Help, Encystment – protozoan Discussions

Write discussion on Encystment – protozoan
Your posts are moderated
Related Questions
What are the three main limiting factors of photosynthesis? The three major limiting factors of photosynthesis process are light intensity, carbon dioxide concentration and tem

Q. Show the important groups of bacteria? The important groups of bacteria are: a) Bacillus: rod-shaped. b) Coccus: spherical. c) Coccobacillus: oval-shaped. d)

The psychological effects of total edentulism are complex and varied, and range from very minimal to a state of neuroticism. Although complete dentures are able to satisfy the esth

Inorganic Nitrogen and Sulphur Metabolism Productivity in agriculture, forestry and other ecosystems is basically limited by the availability of nitrogen nutrients like nitrat

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

LEGAL RIGHTS OF PSYCHIATRIC PATIENTS: When a patient is admitted in psychiatric hospital he may be deprived of  the freedom  to leave the hospital, and also to maintain certai

ACRODYNAM IC S Division of air in lungs. Measured by spirometer. 1. Tidal Air (T.A.): Quantity of air taken in or given out in a breath 500 cc. 2. Inspiratory Reserv

Q. Show the Pre-Diabetes Conditions? Pre-diabetes is a condition which may occur between normal and diabetes stages. It is important for you to know about this group of people,

What are the typical vegetation and the typical fauna of the tropical forests? In the vegetation of the tropical forests broadleaf evergreen trees predominate. On the top of th

In humans, maleness or femaleness is determined by a pair of sex chromosomes called X and Y.    (a) What is the genotype for males?    (b) What is the genot