Kingdom I: Proteobacteria Purple phototrophic bacteria The Nitrifying Bacteria Sulfur- and Iron-Oxidizing Bacteria Methanotrophs and Methylotrophs Pseudomonas and pseudomonads Acetic Acid bacteria Free-Living Aerobic Nitrogen-Fixing Bacteria Neisseria Chromobacterium. and relatives Enteric bacteria Vibrio and photobacterium Rickettsia Spirilla Sheathed Protesbacteria: Sphaerotilus and Leptothrix Budding and Prosthecate/Stalked Bacteria Gliding Myxobacteria Sulfate-and Sulfur-Reducing ProteobacteriaKingdom I: Proteobacteria Purple Phototrophic Bacteria The Nitrifying Bacteria Sulfur- and Iron-Oxidizing Bacteria Methanotrophs and Methylotrophs Pseudomonas and Pseudomonads Acetic Acid Bacteria Free-Living Aerobic Nitrogen-Fixing Bacteria Neisseria, Chromobacterium, and Relatives Enteric Bacteria Vibrio and Photobacterium Rickettsia Spirilla Sheathed Protesbacteria: Sphaerotilus and Leptothrix Budding and Prosthecate/Stalked Bacteria Gliding Myxobacteria Sulfate- and Sulfur-Reducing Proteobacteria