Important Bacterial Groups

1. Important Bacterial Groups In addition to being classified by Gram staining and shape, bacteria are also classified by biochemicalproperties and evolutionary relationships.

2. Proteobacteria • Largest and most diverse group • Several subgroups w/ varying nutritional needs • Aerobic and anaerobic Many live in symbiotic relationships with other organisms.

3. Proteobacteria cont. • Nitrogen-fixing bacteria live in nodules on the roots of legumes (beans, alfalfa, clover etc.) • Atmospheric nitrogen is not in a form usable to plants; without these bacteria plants could not make nitrogen

5. Proteobacteria cont. • Agrobacterium- causes tumors in plants • Rocky Mountain Spotted Fever • Stomach ulcers • E. coli- live in digestive tract • Salmonella- food borne illnesses

6. Rocky Mountain Spotted Fever • …carried by ticks

7. Gram-Positive Bacteria • Very large group • Includes bacteria that cause strep throat • Botulism • Members of the genus Lactobacilli used to make yogurt • anthrax

8. Anthrax- a biological weapon

9. Gram-positive bacteria that grow in soil are used to make antibiotics • What color do they stain? Why?

10. Cyanobacteria • A.k.a blue-green algae • Photosynthetic • Very numerous • Contribute to oxygen-rich atmosphere • Food source to marine animals

11. Spirochetes • Gram negative • Spiral-shapted • Aerobic or anaerobic • Corkscrew rotation • Pathogens or free living • Syphilis • Lyme Disease

12. Chlamydia • Gram negative • Only live inside animal cells which supply them with nutrients and protection • no peptidoglycan Can lead to inability to have children Sometimes no symptoms are observed Can be passed from mother to child