The Non-proteobacteria Gram- Negative Bacteria •G- bacteria not closely related to Proteobacteria •Includes several photosynthetic bacteria •oxygenic and anoxygenic
Jan 11, 2016
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