Our Tax Dollars Paid for This

1. Our Tax Dollars Paid for This

2. Protista / Protozoa Microbiology 2314

5. Protozoa Can Be Human Parasites • A parasite is an organism that obtains food and shelter from another organism and derives all benefits from this association.

6. Characteristics • Abundant / Simplest Animals / Few are Pathogenic

7. Characteristics • Unicellular / Eukaryotic • Chemoheterotrophic (Saprophytic)

8. Characteristics • Aquatic and Terrestrial • Diverse / Population Size Varies by Location

9. Characteristics • Important in Water Quality • Prominent in Soil

12. Growth • Aerobic • pH 3.5 to 9.0 • Mesophiles (High Temps are Detrimental) • Water / Required for Ciliated Forms • Flagellated Forms are More Drought Resistant • Not All Cysts Can Resist Dessication

13. Life Cycle • Active – Trophozoite Stage • Inactive – Cyst Phase

14. Balantidium coli cyst

15. Balantidium coli trophozoite

16. Feeding • Saprophytic • Phagocytic • Pinocytic

17. Selective Feeders

18. Termites & Protozoa = Symbiosis • Protozoa are critical in the digestion of cellulose. Protozoa live in the gut of termites and obtain food from the foraging activities of the insects. In return, the protozoa use their specialized enzymes to break down cellulose, a polymer of glucose, for the insects.

20. How does the toxic substance Sulflurimid work?

21. Protozoa Have An Effect On The Structure And Function Of Microbial Communities

22. Predator Prey Relationship Increases in a bacterial populations are followed by an increase in a protozoan population • Alleopathy (The harmful effect of one organism on another. • Protozoa Can Keep A Microbial Group From Dominating A Given System * Hudson Bay Trading Company

26. When discussing protozoans and bacteria populations, which is the predator and which is the prey?

27. Methods of Reproduction • Asexual 1. Fission 2. Schizogony 3. Budding • Sexual

28. Amoeba

30. Amoebas • Phylum Amoebozoa • Subphylum Sarcodina • Move by Pseudopodia • Entamoeba histolytica / Amoebic Dysentery (Destruction of Red Blood Cells) • Survival Structures / Cysts

32. About 10 percent of the world's population is infected with E. Histolytica. • It is the third most common cause of death (after Schistosomiasis and Malaria) from parasitic infections, and second protozoal cause (after malaria).

33. Very common in South and Central America, West Africa and Southeast Asia. Rare in temperate climates. • About 90% of infections are asymptomatic and the remaining 10% produce a spectrum of disease varying from dysentery to amoebic liver abscess.

37. Cyst of Entamoeba histolytica in a fecal smear Obtained via Fecal/Oral Route

38. Cyst

39. Fecal-Oral Route Protective cysts pass out of the intestines with the feces and are ingested via contaminated food and water by the next host.

40. After ingestion, the trophozoites hatch and penetrate the walls of the large intestine causing ulcerations and symptoms of dysentery.

41. May result in “Bloody Diarrhea”

42. Histological preparation showing cross-section of ulcer. Note the high degree of necrosis in center of ulcer. The amoeba are advancing laterally under the intact mucosa.

43. Smear showing several hematophagous trophozoites.

44. Trophozoite of Entamoeba histolytica.

46. E. histolytica is found primarily in the colon where it can live as a non-pathogenic commensal or invade the intestinal mucosa (green). The amoeba can metastasize to other organs via a hematogenous route (purple); primarily involving the portal vein and liver. The amoeba can also spread via a direct expansion (blue) causing a pulmonary infection, cutaneous lesions or perianal ulcers

47. Acanthamoeba • One of the most common protozoans found in soil • Common in “warm” lakes • Can survive in the space between the contact lens and the eye

48. Acanthamoeba can infect the eye (resulting in blindness), blood, spinal cord, and brain. It is transmitted by waterborne cysts picked up while swimming in contaminated water.