Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact

1. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact PROKARYOTES (CHAPTER 27)

2. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Structure of Prokaryotes

3. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Structure of Prokaryotes Bacteria come in two flavors: Gram positive vs Gram-negative prokaryotes Why are they called “gram-positive” and “Gram-negative”?

4. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Structure of Prokaryotes Gram Staining A simple procedure used to stain bacteria: The thick peptidoglycan cell wall of gram-positive bacteria prevents the stain (crystal violet-iodine) from leaving the cell when decolorization is carried out.

5. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Structure of Prokaryotes Taking advantage of the peptidoglycan cell wall: Penicillin Antibiotic that inhibits enzyme DD-transpeptidase, which is involved in building and rearranging the cell wall. DD-transpeptidase with penicillin bound: penicillin

6. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Structure of Prokaryotes Capsules Capsules surround cell walls of many prokaryotes. Structure: - Composed of polysaccharide or protein Function: - Allows bacteria to bind to other bacteria or to another substrate like your cells. - Protection from immune system

7. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Structure of Prokaryotes Fimbriae and Pili Function: - Allows bacteria to bind to other bacteria or to another substrate like your cells. - Sex pili are specialized pili used during conjugation.

8. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Motility of Prokaryotes Flagella - 50% of prokaryotes capable of directional movement. - Flagella are most common, but not the only means of motility - NOT covered by plasma membrane like in eukaryotes. - Basal apparatus (motor proteins) cause flagella to ROTATE, not whip like in eukaryotes. The very different structures of the prokaryotic and eukaryotic flagella is a clear example of… Is this bacterium gram + or gram -?

9. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Motility of Prokaryotes Taxis Taxis = to move towards or away from a stimulus Chemotaxis – towards (positive) or away (negative) from a chemical. Phototaxis – towards (positive) or away (negative) from light. Bacterium exhibiting positive chemotaxis

10. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Internal and Genomic Organization - membranes Membrane organization reminiscent of mitochondria and chloroplasts

11. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Internal and Genomic Organization - membranes Single circular chromosome in nucleoid region plus plasmids

12. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Reproduction and Adaptation in Prokaryotes - Binary fission (asexual) every 1 to 3 hours (some only 20 min) - ENDOSPORES - Formed by certain bacteria when environment goes south (lacking a nutrient, etc…) - Highly Resistant cells - Bacterium replicates chromosome and surrounds with tough wall. - Remainder of cell breaks down - Most endospores survive boiling and can persist dormant for 100’s of years

13. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotic Nutritional Classes - There are prokaryotes in every nutritional class:

14. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotic Metabolic Relationships to O2 Obligate (strict) aerobes - Use oxygen for cell resp. CANNOT be without it Facultative aerobes - Use O2 if present, switch to fermentation in absence of O2 Obligate (strict) anaerobes - Poisoned by O2 - Two types: 1. Fermentation – bacteria that only do fermentation 2. Anaerobic respiration – use substance other than O2 as final electron acceptor like nitrate (NO3-) and sulfate (SO42-)

15. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Nitrogen Metabolic Nitrogen Fixation N2 NH4+ Nitrogen fixing bacteria take atmospheric nitrogen (N2) and can convert it to NH4 (ammonium) for use in its amino acids and nitrogenous bases. Excess is secreted and used by plants as shown to the right… THIS IS THE ONLY WAY NITROGEN CAN ENTER THE ECOSYSTEM…THIS IS WHERE ALL YOUR NITROGEN COMES FROM!!

16. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotic Metabolic Cooperation Colonial Cooperation: Certain bacteria like the cyanobacterium Anabaenain colonies. Photosynthetic cells are mixed with heterocyst cells, which fix nitrogen only since O2 produced during photosyn. inhibits nitrogen-fixing enzymes.

17. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotic Metabolic Cooperation Biofilms: Surface coatings of cooperating bacteria. Above, dental plaque, a biofilm that forms on tooth surfaces. Channels form in the biofilm to allow nutrients and waste to enter and exit the interior of the film respectively.

18. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotic Phylogeny

19. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Comparing the three domains:

20. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Archaea Bacteria

21. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Archaea Bacteria - “lovers” of extreme conditions Extremophiles 1. Extreme Thermophiles - thrive in hot environments Ex. Sulfolobus – genus that live in sulfur-rich volcanic springs pushing 90°C. 2. Extreme Halophiles - thrive in high salt environments 3. Methanogens - Obligate (strict) anaerobes – poisoned by O2 - Many species live in swamps and marshes - Use CO2 to oxidize H2, releasing CH4 (methane) as waste.

22. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Eubacteria

23. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Eubacteria Fig 27.13 in book

24. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotic Symbiotic Relationships Symbiosis – relationship b/w organisms of different species in direct contact Hst – larger organism Symbiont – smaller organism Three Forms: Mutualism (+/+) Human Intestinal bacteria Commensalism (+/0) Parasitism (+/-) Glowing below eye of flashlight fish is organ containing bioluminescent bacteria. Light used to attract predators and mates. Bacteria gets nutrients from fish.

25. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Pathogenic (parasitic) Prokaryotes - Cause about half of all human diseases **2 to 3 million die a year from lung disease caused by Mycobacterium tuberculosis **2 million others die of diarrheal disease caused by prokaryotes Lyme disease - Most widespread pest-carried disease in United States - Tick carries spirochete Borrelia burgodorfi - The tick is called a vector because it transmits the disease as would a mosquito that transmits the protist that causes malaria.

26. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Pathogenic (parasitic) Prokaryotes - Cause about half of all human diseases **2 to 3 million die a year from lung disease caused by Mycobacterium tuberculosis **2 million others die of diarrheal disease caused by prokaryotes Lyme disease - Most widespread pest-carried disease in United States - Tick carries spirochete Borrelia burgodorfi - The tick is called a vector because it transmits the disease as would a mosquito that transmits the protist that causes malaria.

27. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Pathogenic Prokaryotes Exotoxins Toxic proteins secreted by pathogenic bacteria Ex. Cholera - Caused by Vibrio cholera - Life threatening diarrhea Exotoxin called cholera toxin (CTX) causes intestinal cells to secrete Cl- into gut and water follows by osmosis

28. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Pathogenic Prokaryotes Endotoxins -Toxic lipopolysaccharides (glycosylated phosopholipids) found in outer membrane of Gram negative bacteria. - Released when cell dies and outer membrane breaks down Ex. All members of genus Salmonella - Typhoid fever (fecal oral route) - Food poisoning (esp chicken) Typhoid bacillus (Salmonella enterica)

29. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Prokaryotes in Research, Technology and Society - Convert milk to cheese / yogurt - E. coli in gene cloning - Agrobacterium tumefaciens to make transgenic plants - Bioremediation Use of organisms to remove pollutants from the environment

30. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Protists (Chapter 28) 1. More structural and functional diversity than any other group of organisms… 2. Most are unicellular, some colonial and multicellular… 3. Most nutritionally diverse eukaryotes A. photoautotrophs B. heterotrophs C. mixotrophs – combine photosyn with hetertrophic nutrition

31. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Protists Broken into three general categories based on ecological context: 1. Photosynthetic (plant-like) protists - algae 2. Ingestive (animal-like) protists - protozoans 3. Absorptive (fungus-like) protists

32. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Protists How did such incredible diversity arise? Many species resulted from two rounds of endosymbiosis…

33. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Phylogeny of protists Fig. 28.4 Phylogenetic tree showing the major clades of protists.

34. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Phylogeny of protists Fig. 28.4 What’s a clade? A complete branch of a phylogenetic tree. Above how many clades are highlighted? Two, the blue and the red because these are complete branches. The green is not complete.

35. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Phylogeny of protists Fig. 28.4 Let’s examine a handful of these clades…

36. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Fig. 28.8 Kingdom Euglenozoa Characterized by spiral or crystalline rod within flagella in addition to 9+2 arrangement of microtubules. Cyrstalline structure has unknown function.

37. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Fig. 28.8 Kingdom Euglenozoa Phylum kinetoplastid Ex. Genus Trypanosoma - Causes sleeping sickness - Spread by African tsetse fly - Fatal if untreated - Evade immune system by repeatedly changing the proteins on the surface of the cell

38. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Fig. 28.8 Kingdom Euglenozoa Phylum euglenid Ex. Euglena - Found in freshwater - Photoautotroph if sunlight available otherwise heterotroph by absorbing nutrients from environment (mixotroph)

39. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Phylogeny of protists Fig. 28.4 Let’s examine a handful of these clades…

40. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Fig. 28.8 Kingdom Alveolata Characterized by sacs below membrane called alveoli having yet unknown function

41. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Alveolata Phylum dinoflagellates - Abundant as both marine and freshwater phytoplankton Phytoplankton – phyto = photosynthetic, plankton = “free-drifting” - free-drifting photosynthetic organisms (cyanobacteria is also a large part of phytoplankton) - Bloom (explosion of growth) can cause “red tide” - Secrete toxins that bioaccumulate in molluscs making them dangerous to eat - Have internal “plates” of cellulose giving its characteristic shape…

42. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Alveolata Phylum Ciliates - Obviously use cilia to move and feed Ex) Paramecium Two types of nuclei - Large (macro) nucleus - Smaller (micro) nucleus - Can have more than one of each

43. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Alveolata Phylum Ciliates Macronucleus - Contains dozens of copies of genome - Genes are not on chromosomes (they don’t have chromosome) - Arranged in small units each having many duplicates of a single gene - The gene products (i.e. proteins) control daily functions like feeding, waste removal, etc…

44. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Alveolata Phylum Ciliates Feeding - Mainly on bacteria, which are moved through oral groove and phagocytosed at “cell mouth” into food vacuoles. - Food vacuoles fuse with lysosomes - Undigestable material is egested when lysosomes fuse with cell membrane

45. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Alveolata Phylum Ciliates Reproduction - Mostly asexually by “binary fission” Conjugation - Genetic diversity, NOT REPRODUCTION - two organisms exchange haploid micronuclei (see fig 28.12b above and use book for more detail)

46. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Phylogeny of protists Fig. 28.4 Let’s examine a handful of these clades…

47. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Stramenopila Phylum Diatom (Bacillariophytes) - Unicellular Algae - glass-like silica based cell wall as shown in figure - Protection from predators - Withstand pressures up to 1.4 million kg/m2 (pressure applied by the leg of a table with an elephant standing upon it)

48. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Stramenopila Phylum Diatom (Bacillariophytes) Reproduction - Usually asexually by mitosis - Sexual reproduction is not common, but does occur Diversity - Estimated 100,000 species - Major component of phytoplankton in oceans and lakes

49. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Stramenopila Phylum Golden Algae (chrysophytes) (chrysos = golden) Dinobryon - Contain yellow/brown cartenoid pigments - Freshwater and marine plankton - All obviously photosynthetic, some species mixotrophs - Most unicellular, but some, as shown, are colonial

50. Chapter 27: Prokaryotes - structure, function, diversity, evolution, impact Kingdom Stramenopila Phylum Brown Algae (phaeophytes – guess what phaeo means…) Kelp - Largest and most complex algae (its what you call seaweed) - All are multicellular and most are marine (salt water – ocean) - Common along temperate costs like ours