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1. The Prokaryotes:Bacteria June 10, 2014

2. The Prokaryotes

3. Domain Bacteria • Proteobacteria • Gram-negative • Chemoheterotrophic • Divided into 5 groups • Alphaproteobacteria • Betaproteobacteria • Gammaproteobacteria • Deltaproteobacteria • Epsilonproteobacteria

4. The Alphaproteobacteria • Capable of growth in nutrient-deprived environments • Some contain prosthecae. Stalk like buds function to anchor the bacteria and absorb nutrients • Pelagibacterubique • 20% of prokaryotes in oceans • Constitutes 0.5% of all prokaryotes • 1354 genes (relatively small genome) • Symbiotic bacteria that have lower metabolic requirements have the smallest genomes

5. Figure 11.2b Caulobacter. Insert Fig 11.2b May grow in laboratory water baths

6. The Alphaproteobacteria • Human pathogens (zoonosis) • Bartonella: • B. henselae: cat-scratch disease. Infects RBCs. • Brucella: • B. melitensis: brucellosis. Survives in phagocytes • Obligate intracellular parasites • Rickettsia: arthropod-borne, spotted fevers • R. prowazekii: epidemic typhus. Transmitted by lice. • R. typhi: endemic murine (mice) typhus • R. rickettsii: Rocky Mountain spotted fever. Damage blood capillaries • Ehrlichia: live obligately in white blood cells • Tickborne (Lone star tick) • Causes ehrlichiosis which can be fatal

7. Figure 11.1 Rickettsias. Slime layer Chicken embryo cell Scattered rickettsias Nucleus Masses of rickettsias in nucleus Rickettsias grow only within a host cell, such as the chicken embryo cell shown here. Note the scattered rickettsias within the cell and the compact masses of rickettsias in the cell nucleus. A rickettsial cell that has just been released from a host cell

8. The Alphaproteobacteria • Wolbachia: live in insects and other animals • Only live inside of cells of their hosts (insects) • Difficult to culture • 75% of all species of animals carry this bacteria • May lyse the cells of the infected host or cause the infected host to not reproduce

9. Applications of Microbiology 11.1b In an infected pair, only female hosts can reproduce. Males Females Neither infected Uninfected offspring Male infected No offspring Female infected Infected offspring Both infected Infected offspring Wolbachia Unfertilized female infected Infected female offspring

10. The Alphaproteobacteria • Plant pathogen • Agrobacterium: insert a plasmid into plant cells, inducing a tumor (crown gall)

11. Figure 9.19 Crown gall disease on a rose plant. Crown gall

12. The Alphaproteobacteria • There are some industrial important alphaproteobacteria • Acetobacter • Gluconobacter • Both produce acetic acid (vinegar) from ethanol

13. The Betaproteobacteria • Often uses nutrient substances that diffuse away from areas of anaerobic decomposition of organic matter • Hydrogen gas • Ammonia • Methane

14. The Betaproteobacteria • Burkholderia • Motile (single flagella), aerobic, gram-negative rod • Capable of degrading 100 different organic molecules • Confers the ability to contaminate drugs in hospitals • Nosocomial infections (cystic fibrosis) • Bordetella • Chemoheterotrophic; rods • B. pertussis • Non-motile, aerobic gram-negative rods • Causative agent of pertussis (whooping cough) • Neisseria • Aerobic gram-negative cocci • Inhabits mucous membranes of mammals • Causative agents of gonorrhea and meningococcal meningitis

15. Figure 24.7 Ciliated cells of the respiratory system infected with Bordetella pertussis. B. pertussis Cilia

16. The Gammaproteobacteria • Constitute the largest subgroup of Proteobacteria • Order Pseudomonadales • Gram-negative rods or cocci • Genus Pseudomonas (rods) • Common in soil • Opportunistic pathogens (urinary tract, burns, wounds….may cause sepsis and meningitis) • Capable of growth in antiseptics. High resistance to antibiotics (encodes for efflux pumps) • Excrete water soluble pigments into media (blue-green pigmentation)

17. The Gammaproteobacteria • Pseudomonadales • Genus Moraxella • Aerobic coccobacilli (between coccus and rod) • Conjunctivitis : inflammation of the conjunctiva

18. The Gammaproteobacteria • Legionellales • Legionella • Found in streams, warm-water pipes, cooling towers • Can survive and reproduce within aquatic amoebas • Difficult to eradicate in water systems • L. pneumophiliacauses legionellosis (pneumonia) • Coxiella • Obligate intracellular pathogen • Causative agent of Q fever • Transmitted via aerosols or milk

19. The Gammaproteobacteria • Vibrionales • Facultative anaerobic gram-negative rods • Found in coastal water • Vibriocholerae causes cholera • Profuse and watery diarrhea (dehydration) • V. parahaemolyticus causes gastroenteritis (inflammation of intestines) • May be transmitted to humans via undercooked shellfish

20. Figure 11.8 Vibrio cholerae.

21. Enterobacter Erwinia Escherichia Klebsiella Proteus Salmonella Serratia Shigella Yersinia The Gammaproteobacteria • Enterobacteriales (enterics) • Peritrichous flagella; facultatively anaerobic • Active fermenters of glucose and other carbs • Fimbriae helps bacteria attach to membranes • Sex pili aid in DNA transfer

22. The Gammaproteobacteria • Order Pasteurellales • Haemophilus • Inhabit mucous membranes of upper respiratory tract, mouth, vagina, and GI tract • Requires X (heme) and V (NAD+, NADP+) factors • Laboratory tests for X and V factors help identify organism • Causes meningitis/earaches in children. Epiglotitis, bronchitis, and pneumonia

23. The Deltaproteobacteria • Includes bacteria that are predators of other bacteria • Bdellovibrio • Attacks other gram-negative bacteria • Reproduces in the periplasm of the infecting host • How can Deltaproteobacteria be beneficial?

24. The Epsilonproteobacteria • Gram-negative helical or curved rods • Campylobacter • Microaerophile • One polar flagellum • Leading cause of food-borne gastroenteritis • Helicobacter • Multiple flagella • Most common cause of peptic ulcers in humans • Infection has been associated with the development of stomach cancer • 50% of all humans are colonized with H. pylori