Eukaryotic Pathogens: Algae and Protozoans What types of eukaryotic organisms are pathogenic, and how do they differ fro

1. Eukaryotic Pathogens: Algae and ProtozoansWhat types of eukaryotic organisms are pathogenic, and how do they differ from bacteria? Algae: dinoflagellates and saxitoxin Protozoans Classification and special structures Pseudopodia, flagella, cilia Pellicles, cysts Important protozoan pathogens Amoebic dysentery Balantidiasis (Balantidium dysentary) Giardia, Trichomoniasis, Trypanosomiasis Malaria, Cryptosporidium Eukaryotic pathogens are mostly parasitic and are difficult to target selectively with drugs since their cells are so similar to human cells.

2. Algae:”Plant-like Protists” Based on Nutrition Table 12.1

3. Toxic Algae: Photosynthetic Dinoflagellates • Cellulose in plasma membrane • Unicellular • Algal “blooms” cause “red tides” • Shellfish ingest dinoflagellates; toxin concentrated through food chain • Neurotoxin (saxitoxin) causes paralytic shellfish poisoning

4. Eukaryotic Pathogens: Algae and ProtozoansWhat types of eukaryotic organisms are pathogenic, and how do they differ from bacteria? • Algae: dinoflagellates and saxitoxin • Protozoans • Classification and special structures • Pseudopodia, flagella, cilia • Pellicles, cysts • Important protozoan pathogens • Amoebic dysentery • Balantidiasis (Balantidium dysentary) • Giardia, Trichomoniasis, Trypanosomiasis • Malaria, Cryptosporidium Eukaryotic pathogens are mostly parasitic and are difficult to target selectively with drugs since their cells are so similar to human cells.

5. The Protozoa: Kingdom Protista Table 12.1

6. Protozoa: “Animal-like Protists” Based on Nutritional Mode • Eukaryotic • Unicellular • Chemoheterotrophs • Vegetative form is a trophozoite • Some produce cysts, or dormant forms (often the infective agent) • Some have an outer support layer: pellicle • Asexual reproduction by fission, budding, or schizogony; • Sexual reproduction by conjugation Figure 12.16

7. Pathogenic Protozoans • Protozoans can be studied according to their type of locomotion: • Amoebas (sarcodines) • move using pseudopodia • Ciliates (ciliates) move • using beds of cilia • Flagellates (mastigophorans) • move using one or more flagella • Apicomplexans are non-motile, • intracellular parasites

8. Eukaryotic Pathogens: Algae and ProtozoansWhat types of eukaryotic organisms are pathogenic, and how do they differ from bacteria? Algae: dinoflagellates and saxitoxin Protozoans Classification and special structures Pseudopodia, flagella, cilia Pellicles, cysts Important protozoan pathogens Amoebic dysentery Balantidiasis (Balantidium dysentary) Giardia, Trichomoniasis, Trypanosomiasis Malaria, Cryptosporidium Eukaryotic pathogens are mostly parasitic and are difficult to target selectively with drugs since their cells are so similar to human cells.

9. Important Pathogenic Protozoans • Amoebas • Entamoeba histolytica - amoebic dysentery • Ciliates • Balantidium coli - Severe colitis/dysentery • Flagellates • Giardia lamblia - giardiasis/beaver fever • Trypanosoma brucei -trypanosomiasis/African sleeping sickness • Trichomonas vaginalis - trichomoniasis • Apicomplexans • Plasmodium vivax - malaria • Toxoplasma gondii - toxoplasmosis

10. Amoebic dysentery(Entamoeba histolytica) Amoebic protozoan

11. Pathogenic Protozoans • Amoebas • Entamoeba histolytica - amoebic dysentery • Ciliates • Balantidium coli - Severe colitis/dysentery • Flagellates • Giardia lamblia - giardiasis/beaver fever • Trypanosoma brucei -trypanosomiasis/African sleeping sickness • Trichomonas vaginalis - trichomoniasis • Apicomplexans • Plasmodium vivax - malaria • Toxoplasma gondii - toxoplasmosis

12. Severe colitis/dysentery( Balantidium coli)A Ciliate Parasite primarily of cows, pigs and horses Seen mostly in farm workers and other rural dwellers by ingestion of cysts in fecal material of farm animals Symptoms similar to amoebic dysentery but milder. Only known pathogenic ciliated protozoan

13. Pathogenic Protozoans • Amoebas • Entamoeba histolytica - amoebic dysentery • Ciliates • Balantidium coli - Severe colitis/dysentery • Flagellates • Giardia lamblia - giardiasis/beaver fever • Trypanosoma brucei -trypanosomiasis/African sleeping sickness • Trichomonas vaginalis - trichomoniasis • Apicomplexans • Plasmodium vivax - malaria • Toxoplasma gondii – toxoplasmosis • Cryptosporidium

14. Archaezoa: Troublesome Flagellates • No mitochondria • Multiple flagella • Giardia lamblia • Trichomonas vaginalis (no cyst stage) Figure 12.17b-d

15. Giardiasis -Beaver fever (Giardia lamblia) Cysts shed in feces Flagellated protozoan Trophozoite stage

16. Trichomoniasis (Trichomonas vaginalis) Unusual undulating membrane Flagellated protozoan

17. Trypanosomiasis/African Sleeping Sickness(Trypanosoma brucei) Tsetse fly (intermediate host) Flagellated protozoan

18. Pathogenic Protozoans • Amoebas • Entamoeba histolytica - amoebic dysentery • Ciliates • Balantidium coli - Severe colitis/dysentery • Flagellates • Giardia lamblia - giardiasis/beaver fever • Trypanosoma brucei -trypanosomiasis/African sleeping sickness • Trichomonas vaginalis - trichomoniasis • Apicomplexans • Plasmodium vivax - malaria • Toxoplasma gondii – toxoplasmosis • Cryptosporidium

19. Malaria (Plasmodium vivax)An Apicomplexan ring stage in RBCs gametocytes in RBC Apicomplexan protozoan nonmotile Anopheles mosquito

20. Plasmodium: An Apicomplexan 1 2 Sporozoites undergo schizogony in liver cell; merozoites are produced Infected mosquito bites human; sporozoites migrate through bloodstream to liver of human Sporozoites in salivary gland 9 Resulting sporozoites migrate to salivary glands of mosquito 3 Merozoites released into bloodsteam from liver may infect new red blood cells Sexualreproduction Asexual reproduction 8 In mosquito’s digestive tract, gametocytes unite to form zygote Zygote Intermediate host Female gametocyte 4 Merozoite develops into ring stage in red blood cell Male gametocyte Ring stage 5 Ring stage grows and divides, producing merozoites Definitive host 7 Another mosquito bites infected humnan and ingests gametocytes 6 Merozoites are released when red blood cell ruptures; some merozoites infect new red blood cells, and some develop into male and female gametocytes Merozoites Figure 12.19

21. Toxoplasmosis(Toxoplasma gondii) Apicomplexan protozoan

22. Cryptosporidium (An Apicomplexan) Causes watery diarrhea, dehydration, cramps and nausea Shed in feces; spread easily by contaminated food and water, especially uncooked foods Caused by Crytposporidium parvum

23. Eukaryotic Pathogens: Algae and ProtozoansWhat types of eukaryotic organisms are pathogenic, and how do they differ from bacteria? Algae: dinoflagellates and saxitoxin Protozoans Classification and special structures Pseudopodia, flagella, cilia Pellicles, cysts Important protozoan pathogens Amoebic dysentery Balantidiasis (Balantidium dysentary) Giardia, Trichomoniasis, Trypanosomiasis Malaria, Cryptosporidium Eukaryotic pathogens are mostly parasitic and are difficult to target selectively with drugs since their cells are so similar to human cells.

24. Making a Table to Study and Associate Characteristics