Chapter 1(History)

• Roles of Microbes:

  • Pathogens
  • Autotrophs and decomposers in the food chain
  • Digestive roles
  • Involved in foods and fermentation
  • Source of antibiotics
  • Used in biotechnology and bioremediation
  • Microbes are also studied for disease research
• Biological Research Uses Microbes:

  • Microbes are small in size (nm - μm) and single-celled
  • Large populations of microbes exist, with millions per gram
  • Some prokaryotes have a rapid growth rate, with 30-minute cell division
  • Microbes are used in research for developing vaccines and antibiotics
• Microbial Abundance:

  • Microbes can be found in drilling core samples up to 5km deep
  • Two biospheres exist: surface and "Deep Hot"
  • Microbes show environmental versatility, with anaerobic and sulfur/methane-based metabolism
  • Microbes are also found in undersea vents
• Prokaryotic Microbes:

  • Prokaryotic microbes are classified into 2 domains (Superkingdoms): Bacteria and Archaea
  • Bacteria have varied metabolism, some are pathogens, and the science of Bacteriology studies them
  • Archaea are environmental extremophiles with unique biochemistry and metabolism
• Eukaryotic Microbes:

  • Algae (Protozoa/Plants) are photoautotrophs, aquatic, and can be single or multicellular with cellulose cell walls
  • Fungi are decomposers (Chemoheterotrophs) with chitin cell walls, and can be single or multicellular
• Viruses (Acellular):

  • Viruses have a simple structure with a capsid, nucleic acid, and some have an envelope
  • They require host cells for growth and are studied in Virology
  • Smaller relatives of viruses include viroids and prions
• Eukaryotic Parasites:

  • Protozoa are chemoheterotrophs, single-celled without cell walls, and some may be pathogenic
  • Helminths are worms in the Animal Kingdom, with microscopic life stages and eggs, diagnosed microscopically
  • Arthropods can cause or transmit diseases
• Additional Fields of Study:

  • Immunology
  • Epidemiology
  • Etiology
  • Bioremediation
• Fields of Microbiology:

  • Infection Control
  • Chemotherapy
  • Industrial Microbiology
  • Biotechnology
• History:

  • Documented plagues include Leprosy, Bubonic Plague, Smallpox, and "Great pox"
  • Microscope development by Robert Hooke and Anton van Leeuwenhoek
  • Early microbiologists like Carolus Linnaeus, Schleiden, and Schwann contributed to the field
• Spontaneous Generation versus Biogenesis:

  • Scientists like Redi, Spallanzani, and Pasteur debated the origin of life
  • Pasteur's experiments supported Biogenesis over Spontaneous Generation
• Germ Theory:

  • Koch's postulates and research on Anthrax
  • Contributions of Semmelweiss and Lister to understanding disease transmission
• Immunology:

  • Edward Jenner's work on vaccines
  • Vaccine production techniques like attenuation, heat killing, and recombinant vaccines
  • Contributions of Pasteur and Metchnikoff in immunology
• Recent Advances:

  • Virology advancements by Beijerinck, Stanley, and Hershey and Chase
  • Chemotherapy developments by Paracelsus, Ehrlich, Fleming, and Domagk
• Future Trends:

  • Recombinant microbes for drugs, hormones, and vaccines
  • Gene therapy, bacteriophage therapy, and genomics as future trends in microbiology