Microbiology and Parasitology

• Microbiology


  The study of organisms, living or non-living, that are so small they cannot be seen by the naked eye; microbes
• Cellular microbes (microorganisms)


  • Prokaryotes (bacteria, cyanobacteria, archeans)
  • Eukaryotes (fungi, protozoa, algae)
• Acellular microbes


  • Viruses
  • Prions
• Prions


  Basically not a cell, they're made up of protein mostly found in the brain, they're not a living being (don't grow, die, or use energy), they reproduce via pre-existing prions
• Divisions of microbiology


  • Bacteriology
  • Virology
  • Mycology
  • Parasitology
  • Phycology
  • Immunology
• Thousands of microorganisms inhabit the human body; normal flora (indigenous microflora or indigenous microbiota)
• Some microbes are opportunistic pathogens that colonize our body
• Some microbes are essential to life. Algae & cyanobacteria produce oxygen (photosynthesis)
• Many microbes are involved in the decomposition of dead organisms and the waste products of living organisms. Collectively, they are referred to as decomposers or saprophytes
• Some microbes decompose industrial waste; Bioremediation
• Many microbes are involved in elemental cycles, such as carbon, nitrogen, oxygen, sulfur, and phosphorous cycles
• Some microbes live in the intestinal tracts of animals where they aid in the digestion of food and, in some cases, produce substances that are of value to the host
• E. coli (Escherichia coli) bacteria that live in the human intestinal tract


  • Produce vitamins K and B1, which are absorbed and used by the human body
• Microbes are essential in the field of genetic engineering. Microbiologists have engineered bacteria and yeast to produce a variety of useful substances, such as insulin, various types of growth hormones, interferons, materials for use as vaccines
• Microbes have been used as "cell models"
• Categories of diseases caused by microbes

  • Infectious disease - results when a pathogen colonizes the body and subsequently causes disease
  • Microbial intoxication - results when a person ingests a toxin that has been produced by a microbe
• Anton van Leeuwenhoek


  The first person to see live bacteria and protozoa, sometimes referred to as the "Father of Microbiology", "Father of Bacteriology," and the "Father of Protozoology", created what today are known as single-lens microscopes or simple microscopes
• Robert Hooke


  He discovered the cell, which is the basic unit of living organisms, his discovery heralded the cell theory, designed light microscope, published the book Micrographia
• Louis Pasteur


  • Discovered what occurs during alcoholic fermentation, dealt the fatal blow to the theory of spontaneous generation, discovered forms of life that could exist in the absence of oxygen (introduced the terms "aerobes" and "anaerobes"), developed Pasteurization, discovered the infectious agents that caused silkworm diseases, made significant contributions to the germ theory of disease, championed changes in hospital practices to minimize the spread of disease by pathogens, developed vaccines to prevent chicken cholera, anthrax and swine erysipelas, developed a vaccine to prevent rabies in dogs and successfully used the vaccine to treat human rabies
• Robert Koch


  • Developed methods of cultivating bacteria on solid media, discovered the bacterium (M. tuberculosis) that causes tuberculosis and the bacterium (Vibrio cholerae) that causes cholera, his work on tuberculin (a protein derived from M. tuberculosis) ultimately led to the development of a skin test valuable in diagnosing tuberculosis
• To fulfill Koch's postulates, it is necessary to grow the pathogen in the laboratory (in vitro) in or on artificial media, and to infect laboratory animals with the pathogen being studied
• Some diseases, called synergistic infections, are caused not by one particular microbe, but by the combined effects of two or more different microbes
• Certain pathogens become altered when grown in vitro, some become less pathogenic, whereas others become non-pathogenic, thus they will no longer infect animals after being cultured on artificial media
• Not all diseases are caused by microbes, many diseases such as scurvy & rickets result from dietary deficiencies, some diseases are hereditary, as in sickle cell anemia, others such as diabetes result from malfunction of a body organ, and still others such as cancer of the lungs and skin are influenced by environmental factors. However, all infectious diseases are caused by microbes, as are all microbial intoxications
• Edward Jenner


  Pioneered immunology with the smallpox vaccine
• Joseph Lister


  Father of antiseptic surgery, interested in postoperative sepsis, was attracted by Pasteur's germ theory, invented antiseptic method used in today's modern surgery, invented a machine that could spray and mist out a portion of carbolic acid into the air to kill atmospheric bacteria
• Paul Ehrlich


  He discovered antibodies, "magic bullet", anti-toxins, father of chemotherapy, discovered staining procedure for tubercle bacilli
• Alexander Fleming


  Discovered enzyme lysozyme and antibiotic penicillin, serendipitous accidental discoveries in science
• Hans Christian Gram


  Discovered the "gram stain" to classify bacteria as Gram positive or Gram negative