1. Chapter 24
Bacteria

2. Two Kingdoms of
Prokaryotes

3. Comparing Eubacteria
With Archaebacteria

4. Three Bacterial Cell Shapes

5. Gram Staining

6. Tour of a Bacterium

7. Bacterial Diseases and Modes of Transmission

9. Gram-positive bacteria (Gram +)
Thick layer of peptidoglycan (protein-sugar) complex in cell walls & single layer of lipids
Stain purple
Lactobacilli are used to make yogurt, buttermilk ….
Actinomycetes make antibiotics like tetracycline & streptomycin

10. Gram-negative bacteria (Gram -)
Cell walls have a thin layer of peptidoglycan & an extra layer of lipids on the outside
Stain pink or reddish 
Lipid layer prevents the purple stain & antibiotics from entering (antibiotic resistant)
Some are photosynthetic but make sulfur, not oxygen

12. Mixture of gram positive and gram negative bacteria, G+ purplish, G- Pinkish

13. Bacteria

15. Kingdom Archaebacteria
Found in harsh environments (undersea volcanic vents, acidic hot springs, salty water)
Cell walls without peptidoglycan
Subdivided into 3 groups based on their habitat --- methanogens, thermoacidophiles, & extreme halophiles

16. Methanogens Live in anaerobic environments (no oxygen)
Obtain energy by changing H2 and CO2 gas into methane gas
Found in swamps, marshes, sewage treatment plants, digestive tracts of animals
Break down cellulose for herbivores (cows)
Produce marsh gas or intestinal gas (methane)

17. Extreme Halophiles Live in very salty water.
Found in the dead sea, great salt lake, etc.
Use salt to help generate ATP (energy).

18. Thermoacidophiles (Thermophiles)
Live in extremely hot (1100C) and acidic (ph 2) water
Found in hot springs in Yellowstone national park, in volcanic vents on land, & in cracks on the ocean floor that leak scalding acidic water

19. Kingdom Eubacteria (true bacteria)
Most bacteria in this kingdom
Come in 3 basic shapes --- cocci (spheres), bacilli (rod shaped), spirilla (corkscrew shape)
Bacteria can occur in pairs ( diplo- bacilli or cocci)
Bacteria occurring in chains are called strepto- bacilli or cocci
Bacteria in grapelike clusters are called staphylococci

20. Most are heterotrophic (can’t make their own food)
Can be aerobic (require oxygen) or anaerobic (don’t need oxygen)
Subdivided into 4 phyla --- Cyanobacteria (blue-green bacteria), spirochetes, gram-positive, & Proteobacteria
Can be identified by gram staining (gram positive or gram negative)

21. Disease-causing gram + bacteria produce poisons called toxins
Clostridium causes tetanus or lockjaw
Streptococcus cause infections such as “strep” throat
Staphylococci cause “staph” infections
Also cause toxic shock, bacterial pneumonia, botulism (food poisoning), & scarlet fever
Can be treated with penicillin (antibiotics) & sulfa drugs

24. Nutrient pollution often causes explosive algal growth which depletes waters of oxygen when the algae die. Toxic and foul smelling compounds may also be produced through this process. Nutrient pollution is the single largest pollution problem effecting coastal waters of the United States (Howarth et al., 2000). Most excess nutrients come from discharges of sewage treatment plants and septic tanks, storm-water runoff from overfertilized lawns, golf courses and agricultural fields. Over 60 percent of the coastal rivers and bays in the United States are moderately to severely affected by nutrient pollution (Howarth et al., 2000). (Photo: Weeks Bay NERRS site)