The Prokaryotes: Domains Bacteria and Archaea Chapter 11, part E The Prokaryotes: Domains Bacteria and Archaea

Lactobacillales - Gram (+) cocci and rods Generally aerotolerant anaerobes, lack an electron-transport chain Catalase negative Lactobacillus Streptococcus Hemolysis Alpha Beta gamma Enterococcus Listeria Figure 11.18

Mycoplasmatales Wall-less, pleomorphic 0.1 - 0.24 µm M. pneumoniae Figure 11.19a, b

Actinobacteria High G + C Gram-positive Include Mycobacteria, Corynebacteria, and Actinomycetes. The important pathogenic genus, Mycobacterium, as well as the filamentous genera Streptomyces and Actinomyces, which form conidiospores.

Actinobacteria Often filamentous Lots of antibiotics from this group Actinomyces Corynebacterium Frankia Gardnerella Mycobacterium Acid fast Nocardia Propionibacterium Streptomyces Figure 11.20b

Domain Archaea Hyperthermophiles Pyrodictium Sulfolobus Thermus Archaea lack peptidoglycan. They typically live in extreme conditions Hyperthermophiles Pyrodictium Sulfolobus Thermus Methanogens Methanobacterium Extreme halophiles Halobacterium Figure 11.25

Microbial Diversity Bacteria size range Thiomargarita (750 µm) to nanobacteria (0.02 µm) in rocks Figure 11.26

Microbial Diversity PCR indicates up to 10,000 bacteria/gm of soil. Many bacteria have not been identified or characterized because they: Haven't been cultured Need special nutrients Are part of complex food chains requiring the products of other bacteria Need to be cultured to understand their metabolism and ecological role