Chapter 1


The Main Themes of Microbiology



   Area of biology that deals with living things too small to be seen without magnification




   Include bacteria, fungi, protozoa, algae, and helminthes

   Are responsible for the survival of all other organisms

  Convert gases to a usable form

  Help digest certain foods

  Degrade materials in sewage and wastewater

   Can be free-living or parasitic

   Viruses - noncellular, parasitic genetic elements

   Pathogens - cause disease in plants and animals



Areas of study within microbiology

   Immunology study of the bodys defenses against infection

   Epidemiology monitor and control the spread of diseases in a community

   Biotechnology manipulation of microorganisms to make products in an industrial setting

   Genetic engineering techniques that alter the genetic makeup of organisms


Historical Milestones

   Robert Hooke (1660)

  used a homemade single lens microscope to observe mold

   Anton van Leeuwenhoek (1676)

  Used his homemade microscope to observe the first bacteria and protozoa   (300X)      

   Edward Jenner (1796)

  Introduced the vaccine for smallpox using the cowpox virus Vaccinia

  Started the field of Immunology

   Louis Pasteur (1822-1895)

  Definitively disproved the idea of  spontaneous generation

  Helped clarify the role of microbes in beer and wine making

  Invented pasteurization

   Robert Koch (1843-1910)

  Established Kochs postulates a series of proofs used to establish whether an organism was pathogenic and what disease it caused (germ theory)              

  The suspected causative agent must be present in every case of the disease and absent from healthy hosts

  The agent must be isolated and grown outside the host

  When the agent is introduced to a healthy, susceptible host, the host must get the disease

  The same agent must be re-isolated from the diseased, experimental host

   Ignaz Semmelweis (1848)

  first physician to propose hand-washing before coming into contact with patients

   Florence Nightingale (1854)

  founded worlds first nursing school

   Dimitri Ivanovski (1892)

  isolated the first virus (Tobacco Mosaic Virus)

   Joseph Lister (1867)

  introduced aseptic technique in hospitals

   Francis Rous (1910)

  discovered viruses that cause cancer (Rous sarcoma virus)

   Alexander Fleming (1929)

  discovered penicillin

   James Watson & Francis Crick (1953)

  discovered the structure of DNA

   Herb Boyer and Stanley Cohen (1973)

  cloned the first DNA using plasmids

   Stanley Prusiner (1982)

  discovered prions

   Kary Mullis (1983)

  developed polymerase chain reaction (PCR)



The Scientific Method

   Hypothesis a tentative explanation to account for an observation

   Theory a collection of data that supports the hypothesis




   Science of classifying living organisms


  Discovering new organisms


  Arranging organisms into related groups

  Species contains a group of closely related organisms

  Domain most inclusive category, all living things classified into 3 domains:





  Assigning names to organisms

  Carolus Linneaus - generated our current naming system called Binomial Nomenclature

First word (genus) always capitalized

Second word (species) not capitalized

Both words italicized when typed or underlined when hand-written             

  Staphylococcus aureus, Staphylococcus aureus



Medical Microbiology

   Past Epidemics

  Influenza - over 100 million

  Smallpox - 10 million

  Bubonic plague  - 25 million

  Polio, Measles, Leprosy

  All largely controlled by vaccines and antibiotics


   Emerging Diseases


  Mad Cow Disease

  Ebola virus

  Avian Influenza