Slide Preparation Of Protozoa (Paramecium)

Classification of Paramecium

1. Phylum :- Protozoa → Unicellular
2. Sub-Phylum :- Ciliophora → Ciliary movement in all stages
3. Class :- Ciliata → Cilia present throughout life
4. Sub – Class :- Euciliata → Cytopharynx, contractile vacuole, mega and micronucleus present
5. Order :- Holotricha → Equal cilia.
6. Sub-order :- Trichostomata → Mouth leads in cytopharynx.
7. Family :- Paramecidae → Oral groove present
8. Genus :- Paramecium

Culture preparation of Paramecium

• It is found abundantly in the ponds and ditches in decaying vegetation. For culturing paramecia boil 20 grains of wheat plus 20-25 hay steams in 500 cc of distilled water for about 10 minutes. Keep it in dark and cool place for about four days and inoculate it with few paramecia by a micropipette, within little days. The culture will found to contain numerous paramecia.

Examination in living condition

• For Slide Preparation Of Protozoa (Paramecium) take a clean slide .Through the micropipette put a drop of water from the culture medium of Paramecium Examine the slide under low magnification of compound microscope. Observe the fast moving Paramecia and their cytopharynx. Many protozoan’s’ move very fast. So, they must be slowed down for proper examination.
• This is done in three ways:
  • Protozoan’s are slowed in 10per methyl cellulose solution. Dissolve 10 gm of methyl cellulose solution50cc of water. Boil, cool and make up to 100 cc .The solution slows down the movement. .
  • 2 % sodium carboxymethyl cellulose solution is also good for slowing down protozoan movement. Boil 2gm of sodium methyl cellulose. Cool.
  • Nickel sulphate acts as anaesthetic .By keeping the animal for 15 min can restrict their movement.

Permanent Slide preparation of protozoa

For the free living and fast moving protozoans, they are first made non motile on a glass slide coated with albumin. Then the small drop of culture containing Paramecium is fixed with an equal drop of 1% of Agar solution melted (1gm of Agar in 100 cc of water distillate) at 450 C .The solution become jelly like. The animal may survive for 30 min. They are fixed with 90% alcohol or by a drop of Schaudinn’s fixative.

Pass the slide through descending grade of alcohol 90%, 70%, 50% and 30% and distilled water. Stain both nuclei and cytoplasm by double staining .Stain first with Ehrlich’s haemotoxylin. Destain in acid water and wash in tap water. Again dehydrate in ascending grade of alcohol. After 90% alcohol stain in cytoplasm Eosin .Keep in 100% alcohol, Clear in xylol and mount on D.P.X.

1. Feeding experiment: As Paramecium is a ciliary and selective feeder. The cilia direct the food particles into the cytopharynx or gullet. Its food particles consist of bacterial etc. The food is collected into membranous vesicle which is formed just below the gullet. When the vesicle is filled with food it is detached and is called food vacuole. In paramecium food particle is circulated in the body by more or less definite path by slow streaming movement of endoplasm called cyclosis. Digestion and assimilation take place during the journey of food vesicle, First it is alkaline and then acidic and again alkaline.
2. For observing cyclosis: Take a drop of culture medium of Paramecia over a slide. Add a little yeast Congo red in a drop of water. The Congo red is taken into the food vacuole .Observe under low magnification along with the movement of Congo red in Food vacuole.

Distribution

• It has cosmopolitan distribution.

Habit and Habitat

• Paramecium caudatum is commonly found in freshwater ponds, pools, ditches, streams, lakes, reservoirs and rivers. It is specially found in abundance in stagnant ponds rich in decaying matter, in organic infusions, and in the sewage water. Paramecium caudatum is a free-living organism and this species is worldwide in distribution.

Comments

• Commonly called as slipper animalcule, being microscopic, elongated slipper-shaped, cigarshaped or spindle shaped.
• Most familiar and extensively studied protozoans.
• Anterior end is bluntly rounded, while posterior end is pointed.
• P. caudatum measures 80 to 350 microns, while P. aurelia 170 to 290 microns.
• Pellicle covers the body. It is clear, firm and elastic cuticular membrane. Pellicle has series of polygonal or hexagonal depressions for trichocysts.
• Cilia cover the entire animal. They are hair-like projections of uniform length, except at posterior end where they are longer and at cytopharynx where they form undulating membrane.
• Infraciliary system consists of basal bodies and kinetodesmata.
• Cytoplasm contains ecto- and endoplasm. Ectoplasm has myonemes and rod-shaped trichocysts. Endoplasm contains food vacuoles, granules, meganucleus, micronucleus, anterior contractile, posterior contractile vacuole, fat and glycogen.
• Trichocysts are rod-shaped bodies consisting of lower trichocyst shaft, basal body and projecting cilium. Cilium project through the hexagonal areas. Trichocysts are discharged to anchor with substratum.
• Reproduction is by binary fission, conjugation, endomixis, hemixis and automixis.
• Locomotion is ciliary. Nutrition is holozoic and it shows response to light and temperature, etc.

Identification

• Since the animal contains slipper-shaped body and 2 contractile vacuoles which are star-shaped and has all above features, hence it is Paramecium.