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Gram Positive Bacteria

Gram Positive Bacteria. Grouped based on C + G ratio (nitrogen bases cytosine and guanine) Divided into 2 Phyla Firmicutes (low C + G ) Actinobacteria (High C + G). Firmicutes. Low G + C ratio Includes endospore forming and wall-less bacteria . Phylum: Firmicute 3 Classes: Clostridia

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Gram Positive Bacteria

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  1. Gram Positive Bacteria • Grouped based on C + G ratio (nitrogen bases cytosine and guanine) • Divided into 2 Phyla • Firmicutes (low C + G ) • Actinobacteria (High C + G)

  2. Firmicutes • Low G + C ratio • Includes endospore forming and wall-less bacteria

  3. Phylum: Firmicute • 3 Classes: • Clostridia • Bacilli • Mollicutes (mycoplasmas)

  4. Clostridiales Clostridium Obligate anaerobes Endospores C. tenani – tetanus C. botulinum - botulism Clostridia

  5. Epulopiscium • Very large bacteria • Huge genome • Endosymbiont in surgeonfish • Reproduces by releasing cells through slit

  6. Single Thiomargarita cell • Thiomargarita • gamma Proteobacteria • Anaerobic chemolithotroph that oxidizes sulfur and reduces nitrates • Even larger than Epulopiscium • Large vacuole to increase surface area to volume ratio Fruit Fly

  7. Bacilli • Bacillales • Includes both rods and cocci • Includes medically/ commercially important genera • Bacillus • Endospore-producing rods • Aerobe or facultative anaerobe • B. anthracis- anthrax • B.thuringiensis – insecticide • B. cereus - food borne illness

  8. Staphylococcus - grapelike clusters of cocci • facultative anaerobes • Yellow pigmented colonies • common inhabitant of skin and the nasal cavity • grows in foods with high osmotic pressure • S. epidermidis and S. aureus

  9. S. aureus highly virulent • surgical wound infections • toxic shock syndrome toxin • enterotoxin - induces vomiting • exfolatin toxin – scalded skin syndrome • Folliculitis • Impetigo • MRSA and VRSA

  10. Lactobacillales • Commercially important • Aerotolerant or facultative anaerobes • Lactobacillus • Aerotolerant; Lactic acid fermenting rod • common in vagina, intestinal tract, and oral cavity • used in production of pickles, buttermilk, and yogurt

  11. Streptococcus • chains of cocci • Aerotolerant; Lactic acid fermenter • Pathogenic strains produce multiple extra-cellular enzymes and toxins • Responsible for more illnesses and a greater variety of diseases than any other group of bacteria

  12. Beta-hemolytic streptococci • S.pyogenes • Impetigo, strep throat, scarlet fever, necrotizing fascitis • Alpha-hemolytic streptococci • S. pneumoniae • Pneumonia, ear infections, sinusitis, meningitis • S. mutans • Dental carries

  13. Listeria • Facultative anaerobe • L. monocytogenes • Contaminates dairy products • Psychrotroph • Survives inside phagocytes • May be responsible for stillbirths and birth defects

  14. Mollicutes (mycoplasmas) • Mycoplasmatales • Wall-less, highly pleomorphic • Very small (0.1 - 0.24 µm) • May produce filaments • Degenerative evolution

  15. Mycoplasma • M. pneumoniae • walking pneumonia • Spiroplasma • Corkscrew morphology • plant pathogen and parasite of plant feeding insects

  16. Actinobacteria • High G + C

  17. Mycobacterium • acid fast; aerobic rods; filamentous growth • non-endospore former; mycolic acid • M. tuberculosis – tuberculosis • M. leprae - leprosy • Corynebacterium • Club shaped, metachromatic granules • C. diphtheriae –diphtheria

  18. Propionibacterium • propionic acid fermenter • Important in swiss cheese production • P. acnes commonly found on human skin; primary cause of bacterial acne • Gardnerella • gram variable; highly plemorphic • G. vaginalis – bacterial vaginitis

  19. Actinomycetes • Common soil inhabitants • Branching filaments • Asexual spores • Frankia, Streptomyces, Actinomyces

  20. Streptomyces • most antibiotics are produced by Streptomyces species • about 500 known species • asexual spores (conidospores) • Produce gaseous geosmin

  21. Actinomyces– facultative anaerobes • mouth and throat of animals • A. israelii - actinomycosis (tissue-destroying disease affecting the head, neck, or lungs) • Frankia • nitrogen fixing bacteria • Forms root nodules with alder trees

  22. Domain Archaea • Highly diverse morphology and physiology • Frequently inhabit extreme environments • Three primary groups are halophiles, thermophiles and methanogens

  23. Currently classified into 3 Phyla • Crenarchaeota • Euryarchaeota • Korarchaeota

  24. Euryarchaeota • Gram+ to gram variable halophiles, methanogens and a few thermophiles • Halobacteriales • Obligate halophiles • Bacteriorhodopsin based light capturing system

  25. Methanobacteriales • Methanogens • Convert CO2, H2 and organic acids into methane • Largest known group of archaea • Gram +;Obligate anaerobes

  26. Crenarchaeota • Gram-; most thermophiles • Sulfolobales • acidophilic thermophilic sulfur metabolizers

  27. Desulfurococcales • Hyperthermophiles

  28. Korarchaeota • No members have ever been observed • Known only from environmental rRNA samples

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