Classifying Bacteria Bergey’s Manual of Systematic Bacteriology Classifies bacteria via evolutionary or genetic relationships. Bergey’s Manual of Determinative Bacteriology Classifies bacteria by cell wall composition, morphology, biochemical tests, differential staining, etc.

Prokaryotic Organisms Prokaryotic-means pre-nucleus. Genetic material not enclosed in a special nuclear membrane. What are the other differences between Prokaryotic and Eukaryotic organisms. Prokaryotic organisms are split into two Domains. Bacteria Archaea

The Prokaryotes

Domain Bacteria Phylum Proteobacteria Contains most of the gram negative bacteria. Relationships have been put together via Ribosomal RNA studies. Split up into five classes. Alpha, beta, gamma, delta, and epsilon

Alphaproteobacteria The Alphaproteobacteria contain many bacteria that are capable of nitrogen fixation in symbiosis with plants. What is nitrogen fixation? Also includes several plant and human pathogens.

The Alphaproteobacteria Human pathogens Bartonella B. hensela: Cat-scratch disease Brucella: Brucellosis Can survive phagocytosis, an important element of the body’s defense against bacteria.

The Alphaproteobacteria Obligate intracellular parasites Rickettsia: Arthropod-borne, spotted fevers R. rickettsii: Rocky Mountain spotted fever

The Alphaproteobacteria Plant pathogen Agrobacterium: Insert a plasmid into plant cells, inducing a tumor Figure 9.19

The Alphaproteobacteria Nitrogen-fixing bacteria Rhizobium Fix nitrogen in the roots of plants Figure 27.5, step 5

The Betaproteobacteria Neisseria Usually inhabit the mucous membranes of mammals. N. meningitidis N. gonorrhoeae Figures 11.4, 11.6

The Gammaproteobacteria Pseudomonas Opportunistic pathogens Metabolically diverse Polar flagella Figure 11.7

The Gammaproteobacteria Legionella Found in streams, warm-water pipes, cooling towers L. pneumophilia Legionellosis or legionaire’s disease Figure 24.15b

Enteric Bacteria Genera Escherichia-Very commonly found in human intestines. Known for its ability to cause very serious food-borne disease. Salmonella-Almost all members of this genera are potential pathogens. Serratia-Can be found on catheters, in saline irrigation solutions, and in other supposedly sterile situations. Proteus-very motile genera, many flagella, can cause UTI’s or wound infections.

The Epsilonproteobacteria Helicobacter Multiple flagella Peptic ulcers Stomach cancer Figure 11.12

Cyanobacteria Oxygenic photosynthesis Heterocysts-specialized cells that fix nitrogen.

Firmicutes Low G + C ratio-Guanine and cytosine bases in DNA. Gram-positive bacteria.

Clostridiales Clostridium Endospore-producing Obligate anaerobes C. tetani- tetanus, C. Botulinum- Botulism C. perfringens- gas gangrene, C. difficile- serious diarrhea, Especially when undergoing Antibiotic therapy. Figures 11.15, 11.16

Bacillales Bacillus Endospore-producing rods B. anthracis –cause anthrax Figure 11.17b

Bacillales Staphylococcus S. aureus-cause a lot of hospital infection. MRSA- methicillin resistant S. aureus. Figure 11.18

Members of this genus are probably responsible for more Streptococcus- Members of this genus are probably responsible for more Diseases than any other group of bacteria. Pneumonia, strep throat, cavities, scarlet fever. Figure 11.19

Actinobacteria High G + C-guanine and cytosine levels in DNA. Gram-positive

Important Genera Mycobacterium M. tuberculosis M. leprae-causes leprosy. Propionibacterium-Some species help make swiss cheese, others cause acne. Streptomyces-produce a a large number of antibiotics. Figure 11.21b

Phylum Spirochaetes Treponema T. pallidum is the cause of syphilis. Figure 11.24

Domain Archaea Hyperthermophiles Methanogens Extreme halophiles Pyrodictium Sulfolobus Methanogens Methanobacterium Extreme halophiles Halobacterium Figure 11.26

Homework Write a few sentences about the difference between gram positive cell walls and gram negative cell walls, and how the gram stain came about. Also define: Nitrogen fixation Plasmids Diseases Rocky Mountain Spotted fever Legionellosis MRSA Scarlet Fever Cat-scratch disease Brucellosis Peptic Ulcers (Helicobacter)