Prokaryotes and the Origin of Metabolic Diversity

1
Prokaryotes and the Origin of Metabolic Diversity
2
Prokaryotes

• Kingdom Monera
• Cell wall composed of murein (peptidoglycan)
• includes
• Actinomycetes
• chemoautotrophic bacteria
• cyanobacteria
• endospore forming bacteria
• enteric bacteria
• mycoplasmas
• myxobacteria
• nitrogen fixing aerobic bacteria
• phototrophic anaerobic bacteria
• pseudomonads
• rickettsias
• chlamydias
• spirochetes

3
Actinomycetes

• Colonies of branching hyphae
• reproduction - fragmentation of ends to form
  spores
• organic litter of soil
• Mycobacterium, Streptomyces

4
Chemoautotrophic Bacteria

• Energy from oxidizing NH3, NO3-, H2S, S, and Fe3
  CO2
• obligate aerobes
• aerated soil
• Nitrobactere, Nitrosomonas

5
Cyanobacteria

• Photoautotrophs
• chlorophyll a
• phycobilins
• nitrogen fixation
• in heterocysts
• Nostoc, Anabaena,
• Oscillatoria

6
Endospore Forming Bacteria

• Gram positive, flagellated rods
• endospores
• obligate anaerobes aerobes
• Bacillus, Clostridium

7
Enteric Bacteria

• Gram negative
• facultative anaerobes
• intestinal tracts
• natural
• pathogenic
• Escherichia, Salmonella,Vibrio

8
Mycoplasmas

• Smallest of all cells (0.10-0.25 microns)
• no cell walls
• extracellular growth
• saprobes and animal pathogens
• Mycoplasma

9
Myxobacteria

• Soil dwelling chemoheterotrophs
• gliding movement
• congregate into fruiting masses
• Myxococcus

10
Nitrogen-Fixing Aerobic Bacteria

• Free-living mutualistic
• important in nutrition of plants
• nodules of legumes
• Rhizobium

11
Phototrophic Anaerobic Bacteria

• Do not release oxygen
• strict anaerobes
• ponds, lakes, ocean sediments
• purple green sulfur bacteria
• Chromatium, Rhodospirillum

12
Pseudomonads

• Nearly all aquatic and soil habitats
• rod shaped, Gram negative, lophotrichous
• chemoheterotrophs
• Pseudomonas

13
Rickettsias and Chlamydias

• Obligate intracellular parasites of animals
• reduced Gram negative wall
• Rickettsias alternate between arthropod and
  mammal hosts
• Chlamydias contracted from other humans or birds
• Rickettsia, Chlamydia

14
Spirochetes

• Helical cells
• corkscrew-like movement with internal flagella
• free-living saprobes and parasites
• Borrelia, Treponema

15
Bacterial Shapes

• Three basic shapes
• coccus
• bacillus
• spirillus
• Variations in shapes
• strepto-
• staphlo-
• sarcinae
• diplo
• tetrads
• vibrio

16
(No Transcript)
17
(No Transcript)
18
External Structure

• Flagella
• parts
• hook
• flagellum proper
• rings
• s
• m
• l
• p

19
L ring
P ring
S ring
M ring
20
Flagellum

• Arrangement
• atrichous
• monotrichous
• peritrichous
• lophotrichous
• Composition
• flagellin (protein)
• ?-N-methyl lysine

21
Pilus

• Functions
• F pilus (sex pilus)
• attachment site for bacteriophages
• adherence
• Spines
• Gram (-) marine species
• unknown function

22
Capsules

• Composition
• some have dextrans, levans, or celluloses
• some have above in combination with muceins
• uronic acid
• Pathogenic species often encapsulated

23
Slime Layers

• Gelatinous material on cell walls
• Unorganized

24
Cell Walls

• Functions
• prevent rupture due to osmotic pressure
• support for flagella
• maintain shape of bacteria

25
Cell Walls

• Composition
• diaminopimelic acid (DPA) in those that lack
  lysine
• teichloic acid (formed from N-acetylglucoasamine
  NAG)
• muramic acid (from N-acetylmuramic acid NAM)
• common amino acids
• uncommon amino acids

26
(No Transcript)
27
(No Transcript)
28
Gram Stain
29
Bacterial Structure(Internal)

• Cell Membrane
• similar to fluid-mosaic model in eukaryotic cells

30
Cell Membrane

• Functions
• controls passage of nutrients wastes
• location of several cytochromes for
  photosynthesis and respiration
• location of enzymes for cell wall synthesis
• enzymes for electron transport system

31
Mesosomes

• Mostly in Gram
• pocket-like
• contain tubules or lamellae
• Functions
• cell wall synthesis
• division of DNA
• respiration
• spore formation

32
Genetic Material

• Circular DNA
• Plasmids (DNA)
• capable of independent replication
• gives drug resistance
• not essential for life

33
Ribosomes

• 40 protein, 60 RNA
• 90 of cell RNA is in ribosomes
• 70s (Svedberg sedimentation coefficient)

34
Photosynthetic Apparatus

• Tied to cell membrane
• pigments stored in vesicles or thylakoids

35
Protoplasmic Inclusions

• Non-membrane bound
• Metachromatic granules (volutin)
• stain red with aged methylene blue
• functions
• storage of inorganic phosphates
• storage of food
• Polysaccharide granules
• starch and glycogen

36
Protoplasmic Inclusions

• Membrane Bound
• carboxysomes (fix CO2 in photosynthesis)
• lipids
• gas vacuoles
• aquatic prokaryotes
• functions
• cell buoyancy
• protect from uv radiation
• regulate surface area/volume relationships
• combination of above

37
Protoplasmic Inclusions

• Spores
• bacterial
• endospores
• exospores
• cysts
• conidia

38
Protoplasmic Inclusions

• Spores
• cyanobacteria
• heterocysts
• akinetes

39
Reproduction

• Asexual
• binary fission
• Sexual
• transformation
• conjugation
• transduction

40
(No Transcript)
41
(No Transcript)
42
(No Transcript)
43
(No Transcript)
44
(No Transcript)
45
(No Transcript)
46
(No Transcript)
47
(No Transcript)
48
(No Transcript)
49
Archaebacteria

• Cell walls lack peptidoglycan
• distinct lipid composition of cell membranes
• RNA polymerase and ribosomal protein more
  eukaryotic-like
• live in extreme environments
• methanogens
• halophiles
• thermoacidophiles

50
Methanogens

• H2 used to reduce CO2 to methane (CH4)
• strict anaerobes
• swamps and marshes
• decomposers of sewerage
• farmers use to convert garbage and dung to
  methane
• inhabit guts of animals (termites, cows)

51
Extreme Halophiles

• Live in saline places as Great Salt Lake, Dead
  Sea
• other species simply tolerate saline conditions,
  these thrive
• pink pigment present in some call
  bacteriorhodopsin

52
Thermoacidophiles

• Live in hot, acidic areas
• optimum temperature is 60-80 C and pH of 2-4
• Sulfolobus (hot springs of Yellowstone National
  Park) - oxidizes sulfur