Protozoa (Practical Part) PDF

Characteristics of Protozoan Phyla: 1. The protozoan is a complete organism of one cell, in which all life activities are carried on. 2. Mostly microscopic, although some are large enough to be seen with the unaided eye. 3. Unicellular organisms, no organs or tissues, but specialize...

Characteristics of Protozoan Phyla: 1. The protozoan is a complete organism of one cell, in which all life activities are carried on. 2. Mostly microscopic, although some are large enough to be seen with the unaided eye. 3. Unicellular organisms, no organs or tissues, but specialized organelles are found; nucleus single or multiple. 4. No germ layer present. 5. The chief means by which protozoa move are by: cilia, flagella and pseudopodia. Pseudopodia exist in several forms: a) lobopodia: a large extension of the cell body contain both ectoplasm and endoplasm. b) Filipodia: athin extension, usually branchining and contain only ectoplasm. c) Reticulopodia: that distinguished from the filipoda in that, they are repeatedly rejoin to form a net-like mesh. d) Axopodia: which are long, thin pseudopodia supported by axial rods of microtubules. 6. Nutrition of all types: autotrophic (manufacturing own nutrients by photosynthesis) ,heterotrophic (depending on other plants or animals for food), saprozoic (usually nutrients dissolved in the surrounding medium). 7. Excretion and Osmoregulation: There are a contractile vacuoles, that function principally in osmoregulation. 8. Reproduction; a) asexually by fission, budding. b) sexually, by conjugation or by syngamy (union of male and female gametes to form a zygote). General characteristics of Amoeba proteus: 1. They live in slow streams and ponds of clear water, often in shallow water on aquatic vegetation or on sides of ledges, rarely found free in water, as they require a substratum on which they crawl. 2. They have an irregular shape because of their power to thrust out lobopodia at any point on their bodies. 3. Organelles such as nucleus, contractile vacuole, food vacuoles and small vesicles can be observed easily with light microscope. * Contractile vacuole function principally in osmoregulation. 4. Amebas live on algae, protozoa, rotifers, and even other amebas, upon which they feed by phagocytosis (An amoeba can live for many days without food but decreases in volume during this process). 5. When the amoeba reaches full size, it divides by binary fission with typical mitosis. Amoeba sp.  General characteristics of Paramecium sp.: 1. Paramecia are usually abundant in ponds or sluggish streams containing aquatic plants and decaying organic matter. 2. The Paramecium is often described as slipper shaped, blunt anteriorly and somewhat pointed posteriorly. 3. Locomotion by cilia, cilia are short and usually arranged in longitudinal or diagonal rows and may cover the surface of the organism or may be restricted to the oral region or to certain bands. 4. It has an asymmetrical appearance because of the oral groove, a depression that runs obliquely backward on the ventral side. 5. The pellicle is a clear, elastic membrane that may be ornamented by ridges or papillalike projections. Just bellow the pellicle is the thin clear ectoplasm that surrounds the larger mass of granular endoplasm, embedded in the ectoplasm just below the surface are the spindle-shaped trichocysts, which alternate with the bases of the cilia. 6. Paramecia are holozoic, living on bacteria, algae and other small organisms. Paramecium sp.  General characteristics of Trypanosoma sp.: 1. Their primary mean of locomotion is by flagella. 2. They belong to zooflagellates and live in the blood of fish, amphibians, reptiles, birds and mammals. 3. They usually live in two hosts: a) an invertebrate: either insect or leech, in which they usually infect their alimentary canal. b) a vertebrate host: in which they live in the blood. 4. Some of them are non pathogenic, but others produce severe diseases in humans and domestic animals, for example: Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense cause African sleeping sickness in humans, and Trypanosoma brucei brucei causes a related disease in domestic animals. They are transmitted by the Tsetse fly (Glossina). 5. They feed by absorbing nutrient substances from the host. 6. They reproduce asexually by longitudinal binary fission.  General characteristics of Plasmodium sp. : 1. Plasmodium Belong to Apicomlexa, all Apicomplexans are endoparasites. 2. The presence of certain combination of organelles, the Apical complex, distinguishes this phylum. This apical complex, is usually present only in certain developmental stages (merozoites and sporozoites) of the organism. 3. Locomotory organelles are less obvious in this group than in other protozoa, tiny contractile fibrils can form waves of contraction across the body surfaces to propel the organism through a liquid medium. 4. The trophozoites live intracellularly in the blood corpuscles of its vertebrate host. 5. The parasite is carried by mosquitoes (Anopheles). Plasmodium sp. Life cycle of Plasmodium sp.