MCB 11 - 1ST MODULE

• Microbiology is the Study of organisms and agents too small to be seen by the naked eye (<1mm)
• Microbiology is the study of organisms that can exist as single cells (others are acellular), contain a nucleic acid genome for at least some part of their life cycle, and are capable of replicating that genome
• Epulopiscium lives in the gut of sturgeonfish.
• T. magnifica (2022) has an average cell length of 9000 µm and larger than Thiomargarita namibiensis.
• The science of microbiology revolves around two interconnected themes:

  
  

  1. Understanding the living world of microscopic organisms (as a basic biological science)

  
  

  2. Applying our understanding of microbial life processes for the benefit of humankind and planet Earth (as an applied biological science)
• Importance of microorganisms:

  first living organisms on planet

  live everywhere life is possible

  more numerous than any other kind of organisms

  global ecosystem depends on their activities

  influence human society in many ways
• Basic Microbiology: Interest in specific group of microorganisms and their biology.
• Virology studies viruses. Mycology studies fungi. Phycology: algae Protozoology: protozoa Bacteriology: bacteria
• Applied Microbiology: Applying our understanding of microbial life processes for the benefit of humankind and planet Earth.
• fields of microbiology

  • Medical Microbiology
  • Immunology
  • Public Health Microbiology
  • Food & Dairy Microbiology
  • Industrial Microbiology
  • Agricultural Microbiology
  • Microbial Ecology
• Yeast is a microorganism. Its cells metabolize the carbohydrates in flour and produce carbon dioxide, which causes the bread to rise.
• Saccharomyces cerevisiae, the yeast responsible for making bread rise
• Ötzi the Iceman was Infected with the eggs of the parasite Trichuris trichiura, which may have caused him to have abdominal pain and anemia
• Otzi infected with Borrelia burgdorferi, a bacterium that causes Lyme disease
• Ötzi may have been trying to treat his infections with the woody fruit of the Piptoporus betulinus fungus. This fungus has both laxative and antibiotic properties.
• Ancient Greeks attributed disease to bad air, mal’aria, which they called “miasmatic odors.”
• The Romans also believed in the “miasma” hypothesis and created a complex sanitation infrastructure to deal with sewage.
• In Rome, they built aqueducts, which brought fresh water into the city, and a giant sewer, the Cloaca Maxima, which carried waste away and into the river Tiber.
• Zacharias Janssen

  • invented the first compound microscope (3-10x)
• Athanasius Kircher

  • suggested to be the first to observe microorganisms (20 years before Hooke’s observation; 29 years before van Leeuwenhoek)


  wrote a book chapter, in Latin: “Concerning the wonderful structure of things in nature, investigated by Microscope”
• Antonie van Leeuwenhoek (1676)

  -“wee animalcules”
• Robert Hooke

  • simple compound microscope (30x)
  • “cells” in cork 


  “elongated stalks” (fungi)
• Spontaneous Generation Theory

  -Life emerges from non-living matter;

  -“vital force” required
• Biogenesis Theory

  -“Life begets life”
• Hippocrates, the “father of Western medicine,” believed that diseases had natural, not supernatural, causes
• The historian Thucydides observed that survivors of the Athenian plague were subsequently immune to the infection.

  "the father of scientific history"
• Marcus Terentius Varro proposed that disease could be caused by “certain minute creatures . . . which cannot be seen by the eye.”
• Francesco Redi

  -jar & meat experiment (no eggs on meat when jar was sealed)
• John Needham

  chicken broth, put it into a flask, sealed it, and waited. Soon enough, microorganisms grew. Because of this, people started to believe in Spontaneous Generation even more.
• John Needham's broth became cloudy due to growth of microorganisms.
• Lazzaro Spallanzani

  -disproved John Needham's experiment by using broth in a flask, sealed the flask so that way no air could get in, and boiled it. No organisms grew in that flask. 
• Spontaneous Generation supporters claimed that air was required

  for the vital force to work.
• Franz Schultze – passed air through strong acids
• Theodor Schwann – passed air through red-hot tubes
• Georg Friedrich Schröder & Theodor von Dusch (1850) - filtered air through sterile cotton wool
• Louis Pasteur

  • Experiments with Swan-neck flasks

  Results proved that life did not arise from non-life
• John Tyndall

  ➢ demonstrated that dust carries microorganisms

  ➢ also provided evidence for the existence of exceptionally heat resistant forms of bacteria

  ➢ Developed the process of “tyndallization”

  -delivered the final blow to the spontaneous generation theory
• GERM THEORY OF DISEASE

  -Diseases are caused by specific agents called germs
• Girolamo Fracastoro

  • disease was caused by invisible living creatures
• Agostino Bassi

  • showed that a disease of silkworms was caused by a fungus