The Non-proteobacteria Gram-Negative Bacteria

•G- bacteria not closely related to Proteobacteria •Includes several photosynthetic bacteria

•oxygenic and anoxygenic

• Taxonomy of photosynthetic gram negative, non-proteobacteria:– Cyanobacteria, Chlorobi (green sulfur) and

Chloroflexi (green non-sulfur)

• Gram negative, Proteobacteria – Purple sulfur bacteria (alpha) and purple non-

sulfur bacteria (gamma)

• Cyanobacteria• Blue-green “algae” • Unicellular, filamentous or colonial • Gliding motility or gas vacuoles • Adaptable to nutrient poor environments

– Fix nitrogen (heterocysts) and CO2

Cyanobacteria

• Oxygenic photosynthesis– May be responsible for oxygenating

atmosphere

(CH2O) + H2O + O2

light2H2O + CO2

• Green (Chlorobi) and purple (Proteobacteria) sulfur bacteria – Anoxygenic photosynthesis– produces sulfur rather than oxygen

2H2S + CO2

light

(CH2O) + H2O + 2S0

• Green (Chloroflexi) and purple (Proteobacteria) non-sulfur bacteria– Anoxygenic photosynthesis

– Use organic compounds to reduce carbon dioxide

– Don’t release oxygen or sulfur as by-product

• Chlamydiae• Chlamydia and Chlamydophila

– Collectively called the chlamydias

• gram (-) coccoid• Obligate intra-cellular pathogens• Transmitted by direct contact or airborne • Distinguished by complex life cycle

Unique life cycle with two cellular forms

Elementary body is infectious stage (extracellular)

Reticulate body is reproductive stage (intracellular)

– Chlamydia trachomatis• Trachoma

– Leading cause of preventable blindness• STDs

– Nongonococcal urethritis -most common STD in US

– Lymphogranuloma venereum

– Chlamydophila pneumoniae• mild form on pneumonia

– Chlamydophila psittaci • psittacosis or ornothosis

– transmitted by birds

• Spirochetes– Coiled morphology like a metal spring– Axial filaments– Treponema – causes syphilis– Borrelia – Lyme disease transmitted by ticks or lice– Leptospira – Leptospirosis from urine contaminated water

• Bacteroidetes • Anaerobic rods

• Prevotella– Common inhabitant of human mouth

• Cytophaga

– gliding motility– degrades cellulose and chitin in soil

• Bacteroides– non-motile found in gingival crevices and large

intestine• 1 billion/gram of feces

– Frequently recovered from deep tissue infections– Infections usually caused by puncture wounds or

surgery

• Fusobacteria – Anerobic– Often pleomorphic may be

spindle shaped

• Fusobacterium– Slender pointed rods– Found in gingival crevices

– May be involved in dental abscesses

• Planctomycetes– Budding bacteria that blurs line between cell

type– Planctomyces

• Aquatic stalked bacteria with no PTG in cell wall

– Gemmata• Double membrane around DNA

• Deinococcus– Includes only two species resistant to extreme

environments– Deinococcus radiodurans– Thermus aquaticus