Encystment – protozoan, Biology

Assignment Help:

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.


Related Discussions:- Encystment – protozoan

Erythrocytic cycle, Erythrocytic cycle The cycle that takes place i...

Erythrocytic cycle The cycle that takes place in the body of man who is considered as secondary host is called the erythrocytic cycle. The first stage of the cycle begins

What is the resting membrane voltage of the neuron, What is the resting mem...

What is the resting membrane voltage of the neuron A complete motor neuron is removed from a frog and placed in normal physiological saline at 1 AM.  The neuron is healthy.  At

Pulmonary embolism, Systemic Infection Serious infections increase total...

Systemic Infection Serious infections increase total body metabolism and thus impose hemodynamic burden on the heart. Increased heart rate associated with infections is an addit

Obelia, what are the economic importance of obelia?

what are the economic importance of obelia?

Why the two dna polymerase proteins are oriented in opposite, Which of the ...

Which of the following best defines why the two DNA polymerase proteins that are held by the sliding clamp are oriented in opposite directions? A. The efficiency of replication

What an isotope is, Explain what an isotope is and explain one use of isoto...

Explain what an isotope is and explain one use of isotopes.

Explain e. coli - microbiological study of water, Explain E. coli - Microbi...

Explain E. coli - Microbiological Study of Water? It is always present in human intestine so its presence indicates the faecal pollution and possible presence of other human or

Excretion in animal, Excretio n I n  Animal To give out nitrogenous...

Excretio n I n  Animal To give out nitrogenous waste products after oxidation of food is excretion. EXCRE T O R Y MATERIALS - 1 .      AMMONIA - Animals are

Explain the ps in vcd in cyanotic heart disease, Explain the PS In VCD in C...

Explain the PS In VCD in Cyanotic Heart Disease ? These are peculiar to this group only. It occurs in young infants (usually after two months and rarely after two years), It co

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd