A Seminar report on The Economic importance of

protozoa

By Abhishek GiriM.Sc. (part-I)Roll no. 1326056

Paper – I , Unit - II

A presentation on The Economic importance of

protozoa

What are Protozoan?• Protozoa means “first animals,” and are described as unicellular

eukaryotes (Goldfuss, 1818).

• They are microscopic found in fresh, marine waters & damp soil.

• A protozoan might be Defined as an Organism which is made up of a mass of protoplasm not divided into cells and which carries on all vital activities of life.

• Protozoan are either solitary or colonial.

Economic importance of protozoa

INTRODUCTION

o Protozoan are Ubiquitous.

o They live as commensals & parasites in animals & plants.

o Man is invariably effected by them.

o Some of them are beneficial , while most of them are harmful to man

o Domestic animals are also affected.

A. Beneficial protozoa

• Some protozoa are of great importance for man kind and other animals

• They can be classified into following categories:

1] Helpful in Sanitation

o Protozoan play an important role in sanitary betterment & improvement in keeping water safe for Drinking purpose.

o Protozoan live in polluted water & feed upon waste organic substances & thus purify it.

o Some feed on bacteria & purify the water indirectly.

2] Protozoa as Foodo Though microscopic but directly or indirectly provide source of

food to man, fish, & other animals.

o Larvae of aquatic insects feed on aquatic protozoans, When these larvae of fish, prawns. etc grows to adult becomes a source of food of man.

o Pelagic protozoan like foraminefera and Radiolaria sink after death to the bottom of ocean & forms the food of deep sea fauna.

o Few protozoa have chlorophyll & are capable of synthesizing own food.

foraminiferans

Radiolarian

3] Commensal Protozoao These protozoan are those which live on or in the body of other

animals & derive some benefits from the relationship.o However, the other partner is neither benefited nor injured.

o They may be of two types :-(i) Ectocommensal Protozoa

(ii) Endocommensal Protozoa

(i) Ectocommensal Protozoao They live on the surface of the host

body.

o Ciliates & Suctorians lead an ectocommensal life on molluscs, arthropods, fishes and frogs, etc.

o The host simply act as a substratum for these ectocommensals.

Suctorians

(ii) Endocommensal Protozoa• They live inside the body of the hosts.

For example,a. Trichomonas, Giardia, etc., live as endocommensal within

the alimentary canal of man.b. Entamoeba coli live as endocommensal in alimentary canal

of frogs.c. Balantidium coli feed upon harmful bacteria in the colon.

• They feed on bacteria and so have beneficial effect.

Trichomonas

Entamoeba coli

Balantidium coli

(4) Symbiotic Protozoao Those protozoan lives a symbiotic relationship

with other animals.

o In this association, the two partners become very much dependent on each other that one cannot get along with other & their separation results in the death of both.

For example:-1. Trichonympha & colonympha are intestinal

flagellates present in termites & wood roaches. They help in the digestion of cellulose which is converted to glycogen.

the glycogen is then utilized by both.

(5) Commercial use of Protozoan skeletons o Skeleton of dead Foraminfera and Radiolaria sink in sea &

form oceanic ooze. This solidify & covert to rock strata.

For example:-o Such rock strata are White chalk cliff’s of Dover and

England, and stone beds of paris, Cairo & north America.

o Paris building are built of the limestone which is composed of shells of genus Hiliolina.

o Pyramids of Egypt are constructed by lime-stone deposits of Nummulite shells.

o Sometimes, skeletal deposits are used as filtering & as abrasive.

6] Protozoans in soil

o They play an important role in Soil fertility.o They graze on soil bacteria.o Protozoan also excrete Nitrogen & Phosphorus.

(6) Zoological importance of Protozoa

o Protozoans are ideal material for Cytological, cytochemical, physiological, biochemical & genetical studies, because of their small size, simple organization, quick reproduction & easy availability.

B. Harmful Protozoa

• Almost all harmful Protozoans lead a parasitic mode of life.

• They parasitize almost every plants & animals including man and various animals.

1] Soil Protozoao Several species present in the soil feed upon the nitrifying

bacteria, thus declining their activity & consequently decrease the amount of nitrogen in the soil.

2] Water pollutiono Wherase some are helpful in sanitation, others are responsible

for water contamination, Protozoan of faecal origin.o Uroglenopsis – pollute water by producing aromatic oily

secretion with bad odour which is unfit for human consumption.o CuSO4 is used to kill such protozoans.

o Noctiluca & Gymnodinium- sometimes multiply so extensively that the water becomes red with their bodies. The phenomena is known as “Blooming” & is the cause of “red tides”.

o Larger concentration of these leads to destruction of fish & even poisoning of edible molluscs.

3] Pathogenic Protozoa• Disease producing protozoans are termed as pathogenic

protozoa.• More than 25 different species of parasitic protozoa live in

man alone.

4] Parasitic Protozoao Parasitic protozoans live on or within the body of other

organisms for sake of food, shelter and continuance of race.

o The parasite can be classified into two categories on their occurrence.

1) Ectoparasitic Protozoa : 2) Endoparasitic Protozoa:

1] Ectoparasitic Protozoao They live on the external surface of the host plant or anmal.o Less common.

For example:-1. Hydramoeba hydroxena : ectoparasite of Hydra & feeds on

ectodermal cells.2. Ichthyophthirius multifiliis: ectoparasite of fresh water fishes

causes integumentary blisters.3. Leishmania tropica: ectoparasite of man causes oriental

sores.

Hydramoeba hydroxena

Leishmania tropica

Ichthyophthirius multifiliis

2] Endoparasitic Protozoa• They live inside the body of the host plant or anmal.• more common

Further classified into according to their location in the host body.i) Coelozoic protozoa : living in the body cavity or coelome e.g

Entamoeba,Trichomonas, Balantidium, etc.ii) Histozoic Protozoa : living between the cells of tissues and

body organs e.g., Giardia, Eimeria,, etc.iii) Cytozoic Protozoa : living inside the host’s body e.g.,

plasmodium, leishmania, Haemoproteus, etc.

Haemoproteus

Eimeria

Balantidium

Sarcocystis

o Endoparasitic pathogenic protozoans are further classified according to their exact location in the body :-

1) Endoparasite of mouth : Dwells in mouth or buccal cavity.a. e.g., Entamoeba gingivalis, Trichomonas tenax : - tartar of teeth & abscesses of gums. - causes Pyorrhoea - infection – kissing & feeding in same bowl.

Peridontal disease

b. Leishmania brassiliensis : - dwells in oro-nasal mucous membrane. - causes espundia. - infection – biting of sandfly.

2) Endoparasite of digestive tract : a. e.g.,Entamoeba histolytica : - inhibits intestine of man. - causes amoebic dysentery & ulceration of colon. - infection – ingestion of cyst with food or drinks.

b. Giardia intestinalis : - dwells in large intestine. - causes diarrhoea. - infection – ingestion of cyst with food or drinks.

3) Endoparasite of blood : dwells in blood of vertebratea) e.g., Tryphanosoma sps : - blood of man. - causes Rhodesian sleeping sickness. - infection – bite of Glossina morsitans.

b) Leishmaina sps : - intracellular, in children. - causes Espundia, oriental sores. - infection – bite of sandfly.

4) Endoparasite of Urinogential tract : dwells in urinogenital organs & causes various pathogenic disease.a. e.g., Trichonomas vaginalis : - urinogenital system of women & men. - causes annoying itch, abnormal discharge. - infection – occur directly in coitus.

b. Trichonomas foetus : - urinogenital system of cattle, horses, & sheep. - causes abortions, delayed conceptions & inflammation of sacs. - infection – occur directly in coitus.

3] Other harmful protozoa

Reference Invertebrate Zoology by E.L.jordan & R.S.verma. A textbook on Protozoa by R.L.kotpal. Protozoa by Victor Castillo.

www.britannica.com/.../protozoan/.../Ecological-and-industrial-importan...

www.interlinepublishing.com/user-content-detail-view.php?cid=911

https://www.mgccc.edu/learning_lab/.../CHAPTER_11

THANK YOU