Microbiology and Parasitology

• Robert Hooke (1665)


  • Cell Theory: all living things are composed of cells
  • Cells: "little boxes"; thin slices of cork
• Anton van Leeuwenhoek (1632-1723)


  • "Father of Microbiology"
  • "Animalcules" (little animals)
• Spontaneous Generation Theory (Abiogenesis) (1650-1850)


  Living things came from non-living things
• Francisco Redi (1668)


  Maggots did not arise from decaying meat
• John Needham (1745)


  Organisms developed spontaneously from fluids
• Lazaro Spallanzani (1755)


  Microorganisms from the air might have entered the flasks before they were boiled
• Theory of Biogenesis (1858); Rudolph Virchow


  All living things arise from pre-existing living things
• Louis Pasteur (1822-1895)


  • Microorganisms are present in the air and can contaminate sterile solutions
  • Discovered fermentation & pasteurization
  • Disproved Spontaneus Generation Theory
  • Developed vaccines to fight cholera, anthrax & swine erysipelas
  • Aerobes: microorganisms require oxygen
  • Anaerobes: microorganisms do not require oxygen
• Joseph Lister (1867)


  Aseptic surgery
• Robert Koch (1876, 1881-1883)

  • Germ Theory of Disease: microorganisms have similar relationships with plants and animals
  • Pure Cultures
  • Mycobacterium tuberculosis: causes pulmonary tuberculosis
  • Vibrio cholera: causes cholera
  • Bacillus anthracis: causes anthrax
  • Koch's Postulate (1884): cultured organisms are the same as isolated organisms
• Neisser


  Neisseria gonorrhoeae (causes gonorrhea)
• Metchnikoff, Gram & Escherich (1884)

  • Phagocytosis
  • Gram staining
  • Escherichia coli
• Petri (1887)


  Petri dish
• Kitasato (1889)


  Clostridium tetani: causes tetanus; tennis racquet-shaped/lollipop-shaped
• Von Bering, Ehrlich (1890)


  • Diphtheria antitoxin
  • Theory of Immunity
• Shiga (1898)


  Shigella dysenteriae
• Chagas, Ehrlich (1910)


  • Trypanosoma cruzi
  • Treponema pallidum
• Carolus Linnaeus (1735)


  • Established Linnaean System of Classification
  • Latin scientific names
  • Genus: 1st letter capitalized
  • Species: small letters
• Alexander Flemming (1928)


  Discovered penicillin, the first natural antibiotic
• Microbiology


  Study of very small living organisms or microbes
• Parasitology


  Study of protozoa and parasitic worms and arthropods
• Bacteriophage


  Virus that infects and possibly destroys bacterial cells
• Taxonomy


  • Orderly classification and grouping of organisms into taxa
  • Classification/Taxonomy
  • Nomenclature: provides naming assignments for each organism
  • Identification
• Bacterial Classifications


  • Domain
  • Kingdom
  • Division
  • Class
  • Order
  • Family: human clan
  • Tribe
  • Genus
  • Species: human first name
• Phenotypic differences


  • Serovarieties
  • Serologic differences
  • Biovarieties
• Halophiles


  Salt-loving cells
• Thermophiles


  Heat-loving cells
• Genotype


  Genetic makeup of an organism
• Phenotype


  Observable physical and functional features of an organism expressed by its genotype
• Eukaryotic Cells (Algae, Fungi, Protozoa, Plants and Animals)

  • Larger and contains membrane enclosed organelles/compartments
  • 2 to >100μm in diameter
  • Nuclear material bounded by membrane
  • DNA complexed with histones
  • Membrane-bound organelles
  • Cytoskeleton
• Prokaryotic Cells (Bacteria & Blue-green Algae)

  • Non-compartmentalized
  • <2μm in diameter
  • Nuclear material not bounded by membrane
  • DNA not complexed with histones
  • No membrane-bound organelles
  • No cytoskeleton
• Svedberg units


  Sedimentation rates during high-speed centrifugation
• Genetics


  Study of heredity
• Microbial genetics


  • DNA: discovered by Frederic Miescher (1869)
  • DNA Components: discovered by Phoebus A. T. Levine (1920)
  • Helical Structure: discovered by Rosalind Franklin
  • Three-dimensional structure of DNA molecule: discovered by James Watson & Francis Crick
• Bacteria


  • Unicellular
  • Prokaryotic
  • Not enclosed in a nuclear membrane
  • Single circular chromosome
  • Shapes: rod, bacilli (rod-shaped), cocci (spherical), spirochetes (spiral)
  • Binary fission
• Parasites


  • Multicellular
  • Eukaryotic
  • Live at the expense of their hosts
  • Ascaris lumbicoides: roundworm
  • Enterobius vermicularis: pinworm/seatworm
  • Sarcoptes scabies: scabies
• Protozoa


  • Unicellular
  • Eukaryotic
  • Kingdom Protista
  • Obtain their nutrition through ingestion
  • Locomotive: flagella, pseudopodia, cilia
  • Free-living/Parasitic
  • Pleomorphic: many sizes and shapes
  • Entamoeba histolytica: amoeba
• Archaea


  • Prokaryotic
  • Does not cause disease in humans
  • Methanogens: produced methane as by product
  • Halophiles: live in extremely salty environments
  • Thermopiles: lives in hot sulfurous environments
• Fungi


  • Eukaryotic
  • Unicellular/Multicellular
  • Heterotropic: cannot produce all of its nutrients
  • Mold: filamentous forms that can reproduce asexually and sexually
  • Chitin: special walls
  • Pityriasis versicolor: an-an
  • Tinea pedis: athlete's foot
• Algae


  • Simple, unicellular
  • Photosynthetic eukaryotes
  • Cellulose: cell wall
  • Balance of nature
  • Produces oxygen & carbohydrates
  • Contains chlorophyll
  • Capable of photosynthesis
  • Aquatic environment and damp soil