The Diversity of Prokaryotic Organisms Chapter 11

Domains Bacteria and Archaea One circular chromosome not in a membrane 70S ribosomes No membrane-bound organelles Binary fission rRNA provides evidence of phylogenic differences between the 2 Domains

Domain Bacteria Proteobacteria Includes most of the gram-negative bacteria Phylogeny based on rRNA studies Common photosynthetic ancestor few are still photosynthetic Mythical Greek god, Proteus Largest taxonomic group of bacteria Classes designated by Greek letters

The  (alpha) Proteobacteria Some grow at low nutrient levels Some have unusual morphology Many are agriculturally important several medically important genra

The  (alpha) Proteobacteria Human pathogens: Bartonella - bacillus Cat-scratch disease

Obligate intracellular parasite: Rickettsia – bacillus or coccobacilli Arthropod-borne cause spotted fevers R. typhi - Endemic murine typhus (fleas) R. rickettsii - Rocky Mountain Spotted Fever (ticks)

Have prosthecae: Caulobacter Hyphomicrobium Stalked bacteria found in low nutrient aquatic environment Hyphomicrobium Budding bacteria found in low nutrient environment

Pelagibacter Very small with tiny genome P. ubique is abundant marine microbe

Nitrogen-fixing bacteria: Azospirillum Grows in association with tropical grasses and sugar cane Rhizobia Rhizobium, Bradyrhizobium Infects roots of legumes forming root nodules

Nitrifying bacteria : Chemoautotrophs Oxidize nitrogen Nitrosomonas NH4+  NO2– (ammonium to nitrite) Nitrobacter NO2–  NO3– (nitrite to nitrate)

Plant pathogen: Agrobacterium Inserts plasmid into plant cells, inducing tumors Crown gall

Produce acetic acid from ethyl alcohol: Acetobacter Gluconobacter

Wolbachia Most common infectious bacteria Endosymbionts of insects and other animals

The  (beta) Proteobacteria Utilize nutrients diffusing from areas of decomposition of organic matter hydrogen gas, ammonia, and methane

Thiobacillus Sphaerotilus Chemoautotroph, oxidizes sulfur: H2S  SO42– - hollow sheath - polar flagella - problem in sewage

Spirillum Large, aerobic freshwater bacterium

Neisseria N. meningitidis Meningococcal meningitis N. gonorrhoeae

Bordetella B. pertussis - whooping cough Aerobic, rods or coccobacillus B. pertussis - whooping cough

The  (gamma) Proteobacteria Largest subgroup Great variety of physiological types Includes the enterics

Azotobacter and Azomonas Beggiatoa Chemoautotroph, oxidize H2S to S0 Gliding motility Beggiatoa alba is only species Azotobacter and Azomonas Nitrogen fixing, free-living soil bacteria Large ovoid cell with heavy capsule

Francisella Francisella tularensis – tularemia (rabbit fever) Pleomorphic Francisella tularensis – tularemia (rabbit fever) Resistant to many antibiotics

Pseudomonas Aerobic rods; Polar flagella Extra-cellular and/or florescent pigments Opportunistic pathogen Metabolize wide variety of substrates Resistant to many anti-microbials Denitrification

Legionella L. pneumophilia Found in streams, warm-water pipes, cooling towers L. pneumophilia Causes a form of pneumonia called legionellosis Survive inside aquatic amoeba

Coxiella Coxiella burnetii Q fever Obligate intracellular pathogen transmitted via aerosols or milk Resistant spore–like body

Vibrio Vibrio cholerae V. parahaemolyticus Facultative anaerobic vibrio Vibrio cholerae Cholera Dysentery V. parahaemolyticus Less severe gastroenteritis Undercooked shellfish

Pasteurella P. multocidia - carried by Komodo dragon mainly pathogens of domestic animals Cause pneumonia and septicemia passed to humans from cat and dog bites P. multocidia - carried by Komodo dragon

Haemophilus H. ducreyi H. influenzae inhabit mucous membranes of upper respiratory tract, mouth, vagina, and intestinal tract require heme fraction (X factor) and NAD cofactor (V factor) H. ducreyi Chancroid (STD) H. influenzae meningitis, pneumonia, bronchitis, septic arthritis, earaches

Enterobacteriales (enterics): Facultatively anaerobic, rods Peritrichous flagella Most ferment glucose and other sugars Inhabit intestinal tract of animals (humans)

Enterics Escherichia Salmonella S. enterica – 2400 servors Coliforms – fecal contamination UTI and Travelers Diarrhea Food poisoning – E. coli 0157:H7 Salmonella S. enterica – 2400 servors S. enterica servor typhi – typhoid fever

Enterics Shigella Klebsiella K. pneumoniae – serious form of pneumonia Shigellosis (bacillary dysentery) Klebsiella K. pneumoniae – serious form of pneumonia Some species fix nitrogen

Enterics Yersinia Proteus Y. pestis – plague Swarmer cells UTI and wound infections

The  (delta) Proteobacteria Some species are predators on other bacteria Important contributors to the sulfur cycle

Bdellovibrio Aerobic, rod with polar flagella attack other gram (-) bacteria similar to the way a virus would

Desulfovibrio Human intestinal tract and anaerobic sediments obligate anaerobe, sulfur reducing bacteria Use S for final electron acceptor Release tons of H2S annually

Myxococcus Gliding motility Feed on bacteria they encounter Cells aggregate to form fruiting body loaded with myxospores

The  (epsilon) Proteobacteria Microaerophilic, helical or vibrioid rods Motile by means of flagella

Campylobacter Helicobacter C. fetus C. jejuni H. pylori causes spontaneous abortion in domestic animals C. jejuni leading cause of bacterial diarrhea Helicobacter H. pylori common cause of stomach ulcers