Microbiology

• Microbiology


  The science (logos) of small (micro) life (bios), or the study of living things so small that they cannot be seen with the naked eye
• Microorganisms studied in microbiology


  • Bacteria
  • Viruses
  • Archaea
  • Fungi
  • Protozoa
• Viruses


  Microscopic but not living, they are particles rather than organisms
• Viruses are included in microbiology because of their small size and close relationship with cells
• Microorganisms can be found in every ecosystem
• Microorganisms populate the healthy human body
• Relationships between microorganisms and humans


  • Beneficial
  • Harmful
• Bacteria play a role in the degradation of intestinal contents
• Microorganisms are essential for the recycling of elements, without which life on our planet could not continue
• Microorganisms have been exploited by humans for our own benefit, such as the manufacture of antibiotics and foodstuffs
• Antony Van Leeuwenhoek


  First person to invent the microscope and discover the microbial world
• Leeuwenhoek's microscopes could magnify objects about 200-300 times
• Leeuwenhoek saw minute moving objects and called them "Little animalcules", which we now know as protozoa, yeasts and bacteria
• Leeuwenhoek was the first person to discover microscopes and the presence of bacteria and spirochetes in the mouth
• Theory of Spontaneous Generation (Abiogenesis)


  The assumption that microorganisms were arising by spontaneous generation after the discovery of microorganisms by Leeuwenhoek
• John Needham


  Observed the appearance of microorganisms in putrefying meat and interpreted this as spontaneous generation
• Lazzaro Spallanzani


  Boiled beef broth, sealed the flasks and observed no appearance of microorganisms, disproving the theory of spontaneous generation and proposing the theory of biogenesis
• Theory of Biogenesis


  Every form of life takes its origin from their parents, germ cells or seeds
• Edward Jenner


  Discovered a safe and efficient vaccination against smallpox, which led to its eradication
• Jenner observed that dairy workers exposed to occupational cowpox infection were immune to smallpox
• Pasteur gave the general term "Vaccine" (Vacca = cow) in honour of Jenner's cowpox vaccine, to various materials used to induce active immunity
• Louis Pasteur


  Father of Microbiology, proved the theory of Biogenesis experimentally, worked on souring of wine and beer, discovered pasteurization, and founded the germ theory of disease
• Pasteur discovered the importance of sterilization, and established the importance of cotton wool plugs for protection of culture media from aerial contamination
• Pasteur differentiated between aerobic and anaerobic bacteria and coined the term "anaerobic" to refer to organisms that do not require oxygen for growth
• Pasteur worked on "Pebrine", a silkworm disease caused by a protozoan, and showed that infection can be controlled by choosing worms free from parasite for breeding
• Pasteur developed the process of "attenuation" during his work on "chicken cholera" in fowl, finding that cultures which had been kept in the laboratory for some time would no longer kill the animals as fresh cultures did
• Pasteur's attenuation process is now used in protective vaccination against diseases
• Robert Koch

  Father of practical Bacteriology, perfected many bacteriological techniques, discovered the causative agents of anthrax and cholera, and developed pure culture techniques by introducing solid media
• The use of agar-agar obtained from dried sea weeds (Gelidium Sp.) in the preparation of solid bacteriological media was first suggested by Frau Hesse, the wife of Koch's student
• Alexander Fleming


  Made two major discoveries - lysozyme and penicillin
• In 1922, Fleming discovered lysozyme by demonstrating that nasal secretion has the power of dissolving or lysing certain kinds of bacteria
• In 1929, Fleming made an accidental discovery that the fungus Penicillium notatum produces an antibacterial substance which he called penicillin
• Bacteria with thicker walls are more resistant to antibiotics that target the cell wall.
• Tetracyclines bind to ribosomes and prevent protein synthesis.