Generalities

2. Generalities • Most are unicellular • Some are colonial or multicellular • Most are the simplest of eukaryotes • Some are extremely complex • Some are photoautotrophs (containing chloroplast) • Some are heterotrophs (absorbing organic molecules • Some are mixotrophs (combining photosynthesis and ingestion of food particles) • Some are decomposers (they are similar to fungi)

3. Protists • Ingestive (animal-like); protozoa • Absorptive(fungus-like) but no exact name • Photosynthetic(plant-like); algae (sing. alga) Some are more closely related to plants, fungi, or animals than they are to other protists.

4. Most are aquatic (algae is one of the most important organisms that makes up plankton) • Some are terrestrial • Why do they need moist/wet environments? • Most reproduce asexually (how do they evolve?) • Some have sexual portions of their life cycle

5. Plastids • Many algae contain plastids. A group of structurally similar organelles like the chloroplast. • Chromoplast – store pigments • Amyloplast/Leucoplast– store starch (amylose)

6. Giardiaintestinalis • Trichomonasvaginalis • Trypanosoma • Dinoflagellates (red tides) • Plasmodium • Phytophthorainfestans • Diatoms • Seaweed (brown algae, could also be red or green algae) • Macrocystis • Porphyra • Amoebas • Entamoebahistolytica • Spirogyra • Paramecium • Euglena

7. Homework • Protist name • Photo • Be able to explain the photo • How are humans familiar with this protist • 3 unique facts of the protist • One powerpointslide – email me the slide

8. Giardiaintestinalis • Causes diarrheal illness (waterborne disease) • Found worldwide • Protist is covered by a protective layer forming a “cyst” • Cyst allows it to survive outside the body and in the environment for long periods of time • lives in the intestine of mammals. People are infected by drinking water contaminated with feces • Boiling water first, kills the cysts

9. Trichomonasvaginalis • an anaerobic, parasitic flagellated protozoan • 180 million cases worlwide. • can survive for up to 24 hours in urine, semen, or even water sample. Uses the mucus coated lining of the reproductive / urinary tract to move • Can infect both men and women, considered an STD • Studies suggest that it became pathogenic when Trichomonas acquired genes through horizontal gene transfer from bacteria that also dwell in the vagina. • Feeds on epithelial cells

10. Trypanosoma • Unicellular parasitic protozoa • Feeds on prokaryotes • Causes “sleeping sickness” (Africa) and Chagas disease (Americas). Spread from fresh water to humans by the bite of a fly. • The surface of Trypanosoma is coated with millions of copies of a single protein. By the time your immune system mounts an immune attack against this protein, the parasite switches surface proteins. One third of Trypanosoma’s genome is dedicated to production of these different proteins.

11. Dinoflagellates (red tides) • Some bloom over the summer and reproduce abundantly causing the sea to appear red. • Red tides have increased with the rise in temperature form the ocean • They produce a neurotoxin which affects muscle function in susceptible organisms. • Humans are affected by eating fish or crustaceans that are infected with the toxins • Great diversity • Are capable of producing their own light through bioluminescence, which also makes fireflies glow. • Can also be parasites

12. Plasmodium • Plasmodium causes malaria byspreadingtinyinfectiouscells (sporozoites) into host. • An animal parasite withanintricatelifecycle (withboth sexual and asexual stages) thatrequiresbothmosquitoes and humanstosurvive • Challengestocombat malaria: a.Emergence of varieties of Anopheles(mosquitoes) and Plasmodiumthat are resistanttoinsecticides and drugs b.Plasmodiumismostlyinsidehumancells and continuallychangessurfaceproteinswhichchallengesthesearchfor a vaccine. • SequencingPlasmodium’sgenomecouldhelpscientists target vaccines Thetwo-host lifecycle of Plasmodium

13. Phytophthorainfestans • Has a sexual cycle (once a year) and asexual cycle (every seven days). • Primary origin of the disease is Mexico, and therefore, scientists can find the most resistant varieties of potato to Late Blight in Mexico • Are host-specific parasites. • Infects potatoes = late blight. Leading to agricultural decline Ex. Irish Potato Famine 1840’s

14. Diatoms • External layer made of silica. It consists of two overlapping parts and allows movement and access to environment • Diatoms have existed since the Jurassic period (180 million years) • Most are unicellular but can exist as colonies shaped as ribbons • Make 23% of the primary production of the world, major component of phytoplankton • Used as abrasives, filters and insulation material. • Tool for monitoring environmental conditions of sea (food chain)

15. Brown Algae • A large group of marine multicellular algae • Around 1500-2000 species of brown algae worldwide • Many variations of this species are consumed by humans • A large sprout of this species, blocking sunlight can affect its ecosystem • Largest population of this species is found in the Sargasso Sea.

16. Macrocystis Lives in the oceans of North Americas Pacific Coast, Australia, South America, South Africa and New Zealand It’s a multicellularsporophyte (2n) which is different from most algae which are gametophytes (n) It may grow up to 60 meters in one season (one of the largest protists) Symbiosis between sea otters and kelp: breeding grounds for sea otters, and protection from predators. Sea otters also keep kelp forest healthy by eating animals that graze on kelp.

17. Porphyra • In East Asia, this red algaeisusedto produce nori (Japan) and gim (Korea), themostcommonlyeatenseaweed. • Called red algaebecausethepigmentsgiveit a red color. Thepigmentsabsorbblue and green light whichpenetratefarintothewater • Approximately70 speciesexist. • Porphyraisthemostdomesticated of the marine algae and grows up to15 cm. • In Japan, theannualproduction of Porphyraisvalued at US$ 1 billion.

18. Ameobas • Amoebas live in freshwater and salt water, in soil, and as parasites in moist body parts of animals. • They are composed of cytoplasm divided into two parts: a thin, clear, gel-like outer layer that acts as a membrane (ectoplasm); and an inner, more watery grainy mass (endoplasm) containing structures called organelles. Can have more than one nuclei depending on the species. • The amoeba moves by continually changing its body shape, forming extensions called pseudopods (false feet) into which its body then flows. • When cysts are ingested, there are carried to the small intestine where they are released into the colon. Can cause abdominal distention, dysentery, fever, and hepatitis.

19. Entamoebahistolytica • It infects humans and other primates (about 50 million people worldwide) • Food and water can be contaminated with it • Lives in the digestive tract causing lesions • It may reach the bloodstream and from there reach different vital organs, usually the liver • Worst U.S. infection case was in Chicago from contaminated water leading to 1,000 cases and 58 deaths. • Third leading cause of death due to a parasite, after malaria and schistosomiasis

20. Paramecium • Exchanges genetic information with each other by conjugation (transfer between cells) • Ejects wastes by exocytosis • Absorbs water by osmosis through plasma membrane – bladder like contractile vacuole with radial canals • Food is ingested through a cilia-lined gullet and taken in by endocytosis/phagocytosis • Covered with tiny hairlike structures called cilia which move it through water