Transcript The (gamma) Proteobacteria

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 nonsulfur bacteria (gamma)
• Cyanobacteria
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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
2H2O + CO2
light
(CH2O) + H2O + O2
• Green (Chlorobi) and purple (Proteobacteria)
sulfur bacteria
– Anoxygenic photosynthesis
– produces sulfur rather than oxygen
light
2H2S + CO2
(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
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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
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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