LABORATORIO: PROTOZOANS Animal-like organisms

Goals for today Learn to use the microscope Learn to recognized the various protozoan phyla. Learn their main ‘diagnostic’ characteristics Learn about their biology and their ecological, economic, and medical importance

PROTOZOA Protozoa is a polyphyletic assemblage of animal-like organisms. This mean that many organisms grouped under Protozoa actually evolved independently, from different ancestors. Hickmann et al. 2011

PROTOZOA: What they share Protozoan organisms have two animal like characteristics: – Absence of a cell wall – Presence of at least one motile stage in the life cycle

PROTOZOA: What they don’t have They don’t have organs or tissues BUT have division of labor within the cytoplasm Various organelles within the cytoplasm function as skeletons, locomotory systems, sensory systems, conduction, defense, etc.

PROTOZOA: Where can you find them? Protozoan organisms are found in a variety of habitats: – Free living Fresh, marine, and brackish water Moist soils – Parasites – Symbiotic relationships

PROTOZOA: why are they important? Although protozoa are frequently overlooked, they are ecologically very important: – As predators of algae, bacteria, and microfungi, – Herbivores – Decomposers – Parasites of great medical and economical importance

PROTOZOA: From chaos to ~order Previously they belonged to the Phylum Protozoa where four main groups were recognized: – Flagellates – Amebas – Spore-formers – Ciliates A new classification approach that considers PHYLOGENETICS and uses MOLECULES to construct their relationships recognizes 14 PHYLA !!!

PROTOZOA: Your Tasks – Phylum: Amoebozoa (naked amebas) Species: Amoeba proteus

PROTOZOA: Amoeba proteus Take a slide from your assigned box Look at the Ameba and try to identify the nucleus and pseudopodia, contractile and food vacuoles. We don’t have any parasitic Ameba but learn about this species: Entomoeba gingivalis, where do you think it lives?

PROTOZOA: Amebas Amebas can be naked or enclosed in shells: Amoeba proteus is a naked ameba that lives in freshwater. Usually found in the underside of water plants. Feed on algae, bacteria, protozoans, rotifers, and other microorganisms. They are granulated in appearance

PROTOZOA: Amebas Amebas body: The outer cell membrane= plasmalemma The plasmalemma encloses the cytoplasm: ectoplasm & endoplasm. Amebas Feeding habits: Phagocytosis: engulfing the food Note the food vacuoles. Lysosomes help digestion

PROTOZOA: Amebas Amebas locomotion: Amebas move and change body shape by thrusting out pseudopodia. Pseudopodia are extensions of the cell body.

PROTOZOA: Amebas Amebas excretion: Any undigested product is eliminated at any point of along the plasmalemma. Amebas osmoregulation: Contractile vacuole: increases in size and then ruptures to the outside. This organelle rids the ameba of the excess water taken from food or osmosis. Amebas nucleus: Nucleus is disc shaped and finely granulated.

PROTOZOA: Amebas Amebas reproduction: Asexually by binary fission Animation: bio_ch05_0149_ab_fission.html

PROTOZOA: Your Tasks Phylum: Foraminifera – Marine shelled amebas – Secrete a skeleton of 1 or more chambers – Skeleton: Calcareous or silica, sand or sponge spicules – Long delicate pseudopodia – When died are fall to the bottom of the ocean forming enormous limestone deposits

PROTOZOA: Your Tasks Phylum: Radiolaria – Marine shelled amebas – Secrete a transparent skeleton of silica – Slender pseudopodia come through the shell by pores

PROTOZOA: Your Tasks – Phylum: Euglenozoa Species: Euglena gracilis (or viridis)

PROTOZOA: Euglena Euglena body: Euglena gracilis is greenish because of chloroplasts that contain chlorophyll. Body is covered by a pellicle secreted by the ectoplasm The stigma or ‘eyespot’ is a reddish pigment that is light sensitive Euglena habitat Common in still pools and ponds Euglena locomotion Whiplike flagellum that maybe you can see with reduced light

PROTOZOA: Euglena Euglena osmorregulation: Contractile vacuole eliminates excess of water and waste Euglena Feeding: Photosynthetic Carbohydrates are stored as starch granules and paramylon (carbohydrate similar to starch) Euglena Reproduction Longitudinal fission when is free or encysted

PROTOZOA: Your Task – Phylum: Euglenozoa Species: Trypanosoma

PROTOZOA: Trypanosoma Your instructor will try to find Trypanosoma. So be patient. What diseases are related to this protozoan? Do report on Trypanosoma INSERT VIDEO: MONSTER INSIDE OF ME: Death by Tsetse Fly

PROTOZOA: Trypanosoma Trypanosoma : Parasite that lives in blood or tissues of vertebrates. Some species are not parasites Trypanosoma Feeding: Osmotrophic= absorbs nutrients directly from surrounding blood or body fluids Trypanosoma diseases Sleeping sickness (T. brucei gambiense, T.b. rhodesiense, T. b. brucei). Chagas disease (T. cruzei). Darwin was believed to have had Chagas disease in his trip to Chile. Africa: Tsetse Central and South America “kissing bug”

PROTOZOA: Your Tasks – Phylum: Apicomplexa Species: Plasmodium

PROTOZOA: Plasmodium Your instructor will try to find Plasmodium in the slide. So be patient. What diseases are related to this protozoan? INSERT VIDEO: Monsters Inside Me: Malaria

PROTOZOA: Plasmodium Plasmodium: Causes malaria 300 million people gets malaria every year. 3 million people die every year. Two hosts: – Anopheles mosquito (female) – Human

PROTOZOA: Your Tasks – Phylum: Ciliophora Species: Paramecium

PROTOZOA: Paramecium Paramecium: Ciliado that inhabits fresh water environments. Paramecium movement: Very active and fast! Movement by ciliary action Paramecium Body : Mouth=cystostome Body cover by a pellicle Two nucleus: macro & micro nucleus

PROTOZOA: Paramecium Paramecium osmorregulation: Contractile vacuole. Located at the end of the body Paramecium nucleus: Macronucleus: regulates metabolism of the cell Micronucleus: contains the animal genome and is in charge of reproduction. Paramecium Trychocysts: Is a structure under the pellicle that when explodes releases a liquid that hardens in water. Believed to have a protective function. When a paramecium feels threatened, trychocysts shoot out from the cell membrane like miniature arrows Discharged trychocysts

PROTOZOA: Paramecium Paramecium feeding: Holozoic= feed on particucles e.g., bacteria The anal pore (cytoproct) is located between the mouth and the posterior end of the body. The anal pore is temporary only when food is discharged.

PROTOZOA: Paramecium Paramecium reproduction: Conjugation Binary fission Conjugation: oral grooves are attached

PROTOZOA: Your Tasks – Phylum: Ciliophora Species: Vorticella

PROTOZOA: Vorticella Solitary Sessile ciliates Ponds and streams Stalk= is long ‘threat-like’ structure that attach it to the substrate. Body is bell shape Peristoma contains the oral disc. Macronucleus is U shape Reproduction is by binaary fission and budding

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