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.
AppliedMicrobiology: 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