Bacterial Replication

Binary fission (JTojnar 2010, WikiMedia Commons)

Replication normally occurs by binary fission and ranges from every 20 mins (e.g. Staphylococci) to 2 weeks (e.g. leprosy bacillus)

  • Variation can occur either by mutations in their DNA, or by lateral gene transfer:
    • Transformation- small, naked pieces of DNA are directly transferred between bacteria, e.g. S pneumoniae
    • Transduction- viruses known as bacteriophages transfer the DNA, many genes encoding toxins are transferred this way
      Conjugative plasmids (Magnus Manske 2006, WikiMedia Commons)
    • Conjugation- DNA is transferred in the form of plasmids, genes encoding antibiotic resistance are typically transferred this way.

Typical requirements of bacteria

  • Atmospheric requirements:
    • Obligate aerobe- e.g. B. bronchoseptica
    • Facultative (optional) anaerobe-e.g. E. coli
    • Obligate anaerobe- e.g. F. necrophorum
    • Microaerophil- e.g. C. jejuni
    • Aerotolerant- e.g. S. dysgalactiae
  • pH- most pathogens require a neutral pH, although some need acidic/alkali environments:
    • Acidophilic- Lactobacillus
    • Alkophilic- Vibrio

Replication of E. coli [1]


Bacterial Replication Learning Resources
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