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The Diversity of Prokaryotic Organisms Chapter 11.

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Presentation on theme: "The Diversity of Prokaryotic Organisms Chapter 11."— Presentation transcript:

1 The Diversity of Prokaryotic Organisms Chapter 11

2 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

3 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 Domain Bacteria

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

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

6 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)

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

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

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

10 Nitrifying bacteria : –Chemoautotrophs –Oxidize nitrogen Nitrosomonas NH 4 +  NO 2 – (ammonium to nitrite) Nitrobacter NO 2 –  NO 3 – (nitrite to nitrate)

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

12 Produce acetic acid from ethyl alcohol: –Acetobacter –Gluconobacter

13 Wolbachia –Most common infectious bacteria –Endosymbionts of insects and other animals

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

15 Thiobacillus –Chemoautotroph, oxidizes sulfur: H 2 S  SO 4 2– Sphaerotilus - hollow sheath - polar flagella - problem in sewage

16 Spirillum –Large, aerobic freshwater bacterium

17 Neisseria –N. meningitidis Meningococcal meningitis –N. gonorrhoeae

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

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

20 Beggiatoa –Chemoautotroph, oxidize H 2 S to S 0 –Gliding motility –Beggiatoa alba is only species Azotobacter and Azomonas –Nitrogen fixing, free-living soil bacteria –Large ovoid cell with heavy capsule

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

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

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

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

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

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

27 Haemophilus –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

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

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

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

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

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

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

34 Desulfovibrio –Human intestinal tract and anaerobic sediments –obligate anaerobe, sulfur reducing bacteria –Use S for final electron acceptor –Release tons of H 2 S annually

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

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

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


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