Microbio

• Microbiology


  The study of microorganisms, usually less than 1mm in diameter which requires some form of magnification to be seen clearly
• Microorganisms studied by microbiologists

  • Viruses
  • Bacteria
  • Fungi
  • Algae
  • Protozoans
• Some organisms studied by microbiologists can be visualized without the aid of amplification
• Bread molds (fungus) and filamentous algae are included in the discipline of microbiology because of similarities in properties and techniques used to study them
• Techniques necessary to isolate and culture microorganisms

  • Isolation
  • Sterilization
  • Culture in artificial media
• Microbiologists may be interested in specific types of organisms

  • Virologists - viruses
  • Bacteriologists - bacteria
  • Phycologists or Algologists - algae
  • Mycologists - fungi
  • Protozoologists - protozoa
• Microbiologists may have a more applied focus

  • Medical microbiology, including immunology
  • Food and dairy microbiology
  • Public health microbiology
  • Industrial microbiology
  • Agricultural microbiology
• Microbiologists may be interested in various characteristics or activities of microorganisms

  • Microbial morphology
  • Microbial cytology
  • Microbial physiology
  • Microbial ecology
  • Microbial genetics and molecular biology
  • Microbial taxonomy
• Lucretius, a Roman philosopher (98-55 B.C.), and Girolamo Fracastoro, a physician (1478-1553) believed invisible creatures were responsible for disease
• Franscesco Stelluti observed bees and weevils using a microscope in the early 1600s
• Anton van Leeuwenhoek (1632 - 1723) was the first to report microorganisms (Royal Society) (Animalcules)
• Spontaneous Generation


  The belief that life could originate from non-living or decomposing matter
• Supporters of Spontaneous Generation

  • Aristotle (384-322 BC)
  • John Needham (1713-1781)
  • Felix Pouchet (1859)
• Disprovers of Spontaneous Generation

  • Francesco Redi (1626-1697)
  • Schwann, Friedrich Schroder and von Dusch (1830s)
  • John Tyndall (1820-1893)
  • Louis Pasteur (1822 - 1895)
• Louis Pasteur disproved the theory of spontaneous generation
• Agostino Bassi (1773 - 1856) showed that a silkworm disease was caused by a fungus
• M. J. Berkeley (ca. 1845) demonstrated that the Great Potato Blight of Ireland was caused by a Fungus
• Louis Pasteur showed that the pébrine disease of silkworms was caused by a protozoan parasite
• Joseph Lister (1827 - 1912) developed a system of surgery designed to prevent microorganisms from entering wounds
• Charles Chamberland (1851 - 1908) identified viruses as disease-causing agents
• Edward Jenner (ca. 1798) used a vaccination procedure to protect individuals from smallpox
• Louis Pasteur developed vaccines including those for chicken cholera, anthrax, and rabies
• Ignaz Semmelweiss (~1850) demonstrated that childbed fever (puerperal fever) was transmitted to patients by doctor's hands
• Emil von Behring (1854 - 1917) and Shibasaburo Kitasato (1852 - 1931) induced the formation of diphtheria tetanus antitoxins in rabbits
• Elie Metchnikoff (1845 - 1916) demonstrated the existence of phagocytic cells in the blood
• Robert Koch (1843 - 1910) established the relationship between Bacillus anthracis and anthrax using Koch's Postulates
• Koch's Postulates


  • The causative (etiological) agent must be present in all affected organisms but absent in healthy individuals
  • The agent must be capable of being isolated and cultured in pure form
  • When the cultured agent is introduced to a healthy organism, the same disease must occur
  • The same causative agent must be isolated again from the affected host
• Fannie Hesse proposed using agar as a solidifying agent for culture media
• Richard Petri developed the Petri dish
• Edward Jenner discovered that cowpox (vaccinia) induced protection against human smallpox
• Vaccination


  Inoculation of healthy individuals with weakened (or attenuated) forms of microorganisms, that would otherwise cause disease, to provide protection, or active immunity from disease upon later exposure
• Pasteur and Roux reported that incubating cultures longer than normal in the lab resulted in ATTENUATED bacteria that could no longer cause disease
• Pasteur and Chamberland developed attenuated vaccines for chicken cholera, anthrax, and rabies
• Emil von Behring and Shibasaburo Kitasato induced the formation of diphtheria tetanus antitoxins in rabbits which were effectively used to treat humans
• Louis Pasteur demonstrated that alcoholic fermentations were the result of microbial activity
• Sergei Winogradsky worked with soil bacteria and discovered that they could oxidize iron, sulfur, and ammonia to obtain energy
• Martinus Beijerinck isolated aerobic nitrogen-fixing soil bacteria (Azotobacter and Rhizobium) and sulfate reducing Bacteria
• George W. Beadle and Edward L. Tatum studied the relationship between genes and enzymes using the bread mold, Neurospora
• Salvadore Luria and Max Delbruck demonstrated spontaneous gene mutations in bacteria
• Oswald T. Avery, Colin M. MacLeod, and Maclyn McCarty provided evidence that deoxyribonucleic acid (DNA) was the genetic material and carried genetic information during transformation