Most are G-, chemohererotrophs, photosynthetic ancestor.
Alpha: Agricultural importance.
Beta: Decay, nitrogen, sulphur.
Gamma: Most diverse of Proteobacteria.
Delta: Predatory, prey on other bacteria.
Epsilon: Helical or vibrioid.
G-, not closely related to proteobacteria.
Firmicutes: Low G + C content.
Actinobacteria: High G + C content.
G-, helical rod, axial filaments, in contaminated water / soil / sewage / decaying matter / animal mouths.
G-, anaerobic, rod, in human intestines, most common on / in us.
G-, ovoid, obligate intracellular in eukaryotic cells.