INTRODUCTION TO MICROBIOLOGY

Cards (22)

  • Definition of Microbiology:
    • Study of organisms and agents too small to be seen clearly by the unaided eye
    • Study of microorganisms
  • Microorganisms are categorized into two groups:
    • Cellular (prokaryotes: bacteria, cyanobacteria, archaeans; eukaryotes: fungi, protozoa, algae)
    • Acellular (viruses)
  • Importance of Microbiology:
    • Microbes perform a range of functions in everyday life and industries
    • Microorganisms are sources of antimicrobial agents and decomposers
    • Microbiology plays a role in disease management and faces challenges like antibiotic resistance
  • Discovery of Microorganisms:
    • Francesco Stelluti made the earliest microscopic observations in 1625-1630
    • Robert Hooke published the first drawing of a microorganism in 1665
    • Antony van Leeuwenhoek made extensive, accurate observations of microorganisms
  • Theory of Spontaneous Generation:
    • People believed in spontaneous generation, challenged by Francesco Redi
    • Lazzaro Spallanzani improved on Redi's experiments
    • Louis Pasteur disproved spontaneous generation with the germ theory
    • John Tyndall demonstrated that dust carries germs
  • Golden Age of Microbiology:
    • Pasteur's work ushered in the Golden Age
    • Disease-causing microbes were discovered
    • Techniques for isolating and characterizing microbes were improved
    • Robert Koch demonstrated the role of bacteria in causing disease and developed Koch's postulates
  • Koch isolated suspected bacterial pathogens in pure culture, containing only one type of microorganism
  • Koch initially cultured bacteria on cut, boiled potatoes, but later developed culture media using meat extracts and protein digests
  • Fannie Eilshemius Hesse suggested the use of agar as a solidifying agent for culture media
  • Koch and his associates developed media such as nutrient broth and nutrient agar
  • Richard Petri developed the petri dish for holding solidified media in Koch's laboratory
  • Pasteur and Roux discovered that incubating cultures for long intervals attenuated bacteria, making them lose their ability to cause disease
  • Attenuated cultures were used as vaccines to protect against diseases
  • Pasteur prepared rabies vaccine by growing the pathogen in an abnormal host, the rabbit
  • Emil von Behring and Shibasaburo Kitasato injected inactivated toxin into rabbits to produce antitoxins for diphtheria and tetanus
  • Elie Metchnikoff discovered phagocytes and phagocytosis in blood cells
  • Industrial microbiology developed from Pasteur's work on alcoholic fermentations
  • Microbial ecology studies the ecological role of microorganisms in carbon, nitrogen, and sulfur cycles
  • Martinus Beijerinck isolated nitrogen-fixing bacteria like Azotobacter and sulfate-reducing bacteria
  • Microbiology has basic divisions like bacteriology, mycology, protozoology, immunology, virology, nematology, and applied aspects for practical problems
  • Major fields of microbiology include medical microbiologists, public health microbiologists, immunologists, agricultural microbiologists, microbial ecologists, food and dairy microbiologists, and industrial microbiologists
  • Microbiologists study microbial physiology, biochemistry, genetics, and molecular biology to understand genetic information and its regulation in cells and organisms