Evolution of Microbial Life

1. Evolution of Microbial Life Bio 100 Tri-County Technical College Pendleton, S. C.

2. Prokaryotic Domains • Domain Bacteria and Domain Archaea • Domain Archaea • do not have the same cell wall composition as the members of the Domain Bacteria • one group produces methane from carbon dioxide and hydrogen • another group requires high salt concentration for survival • another group grows in hot, acidic waters

3. Domain Bacteria • includes those bacteria that cause disease in humans, animals, and plants • have a circular chromosome • no nuclear membrane • cell walls are made of peptidoglycan (part peptide and part carbohydrate) • most species are nonpathogenic and are even beneficial to humans

5. 3 Shapes of Cells-D. Bacteria • Bacillus (plural, Bacilli) • rod-shaped • Coccus (plural, cocci) • ball-shaped or spherical-shaped • Spiral-shaped • vibrio-- shaped like a comma • spirilla and spirochetes -- both corkscrew shaped

6. Rod-shaped Bacteria

7. Cocci

8. Spiral-shaped bacteria

9. A few disease-causing (PATHOGENIC) species • Streptococcus pyogenes • causes strep. throat • Treponema pallidum • causes syphilis • Staphylococcus aureus • causes abscess-type infections • Mycobacterium tuberculosis • causes tuberculosis

11. Gram reaction • Based on amount of peptidoglycan in cell wall • Gram + cells (purple/blue) have lots of peptidoglycan in wall • Gram – cells (red/pink) have much less in their cell wall • Important in treating the organism • Exotoxin versus endotoxin • “Feel worse before feeling better”

12. To spore or not to spore… • Endospore is tough resistant structure made by some bacterial cells that allow survival in inhospitable environment • Mostly Gram positive bacilli • Curse of the Mummy’s tomb and Grandma’s pressure cooker • 100s of hours in boiling water and able to germinate

13. Binary fission • Means “splitting in two” • NOT mitosis since prokaryotes DO NOT have a nucleus • Copy genetic material, grow longer, and divide cytoplasm (Chalk-talk time) • Time variable, some can undergo process every 20 minutes (calculate using 24 hours)

14. Energy and Carbon • Expand to detail both source of energy and carbon • Photoautotroph = light and carbon dioxide-cyanobacteria • Chemoautotroph = chemical reaction/CO2-Nitrobacter/Thiobacillus • Photoheterotroph = light/CR-Purple nonsulfur and green nonsulfur bacteria • Chemoheterotroph = CR/CR-most bacteria

15. Recyclers and Detritivores • If some prokaryotes did NOT function as recyclers, elements would be in short supply • Important in many cycles: carbon, nitrogen, oxygen, and others • Detritivores breakdown organic wastes and dead organisms by decomposing organic wastes • Without them, we would be up to our necks in dead organisms and poo-poo

16. Bioremediation • Defined as using a microorganism to correct or address one of our boo-boos • Oil-eating bacteria; heavy metal eating bacteria, and hazardous chemical ingesting organisms • Biotechnology defined as using a microorganism to produce a useful product • Yeast and booze; bacteria and acetone

17. Endosymbiotic Theory • Endo = “in” or “into” or “inside” • Symbiosis = “living together” • My side simply NOT going there…. • Chalk-talk time again • Simply states that at one time a prokaryotic cell began to “exist” inside another prokaryotic cell

18. Kingdom Protista • all have eucaryotic cells • most are unicellular • algae, protozoa, and fungal-like protists • contain the usual organelles found in eucaryotic cells • much larger than procaryotic cells • some examples of protists

19. Example Protists Protozoa

20. Apicomplexans • unicellular parasites of animals (nonmotile) • Plasmodium spp. • causes malaria • Toxoplasma gondii • causes toxoplasmosis • Cryptosporidium spp. • causes acute disease which may be life-threatening in AIDS patients

22. Plasmodium spp.

23. Flagellates • Motility by means of flagella • Trichomonas vaginalis • causes vaginitis and urethritis in humans • moves by an undulating membrane • Giardia lamblia • causes “backpackers disease” in humans • moves by flagella

24. Trichomonas vaginalis

25. Euglena spp. • photosynthetic and move by means of flagella • Hemoflagellates • transmitted by blood-feeding insects into the bloodstream of bitten hosts • Trypanosoma brucei gambiense • causes African Sleeping Sickness

26. Euglena spp.

27. Trypanosoma spp.

28. Ciliates (Ciliophorans) • move around by cilia • most are non-pathogenic • Paramecium spp. • some are pathogenic • Balantidium coli-- severe dysentery

29. Paramecium spp.

30. Sarcodinians (amoebas) • move around by pseudopods • most are harmless • Amoeba proteus • Entamoeba histolytica • causes amoebic dysentery

31. Example Protists Algae

32. Dinoflagellates • unicellular • live in salt and fresh waters • live near the surface • carry out photosynthesis • producers in many aquatic food chains • some species cause “red” tides

33. Diatoms • have a shell composed of silica • shoe box and lid • diatomaceous earth • sediments of dead diatoms • useful for mild abrasives

34. Brown Algae • large and complex algae • multicellular and marine • photosynthetic • most commonly called “seaweeds” along with red algae and green algae • Live in relatively deep water beyond intertidal zone

35. Brown Algae

36. Red Algae (rhodophytes) • contain phycoerythrin • some are not red • most are marine • most are multicellular and designated as “seaweeds” • Live in the deepest waters • some have life cycles similar to land plants

37. Red Algae

38. Green Algae (chlorophytes) • most live in fresh water • contain chlorophyll • some are unicelluar, colonial and multicellular • cell walls contain cellulose • the “green stuff” growing in a farm pond

39. Green Algae

40. Example Protists Fungal-like

41. Slime Molds • The look like what their name suggests. • Plasmodium -- large, amoeba-like, flat layer that is a feeding stage • Sporandium -- a stage that looks like a mold and produces spores • Often seen on leaf mulch, soil, and rotting logs

42. Slime Molds Sporangia Plasmodium