History of Microbiology;
Spontaneous Generation
Nestor T. Hilvano, M.D., M.P.H.
Images Copyright by Bauman, Robert. 2009. Microbiology, With
Diseases by Taxonomy, 3rd edition, Pearson Benjamin Cummings
Learning Objectives
You should be able to:
1.
Describe the contributions of Leeuwenhoek.
2.
List six groups of microorganisms.
3.
Differentiate between prokaryotic and eukaryotic organisms.
4.
List and answer four questions that propelled research into what is
called “the Golden Age of Microbiology.”
5.
Compare and contrast the investigations of Redi, Needham ,
Spallanzani, and Pasteur to disprove spontaneous generation.
6.
Discuss the significance of Pasteur's fermentation experiments to our
world today.
7.
Identify the scientist whose experiments led to the field of biochemistry
and the study of metabolism.
8.
Name two scientists whose work with vaccines began the field of
immunology.
9.
List four major questions that drive microbiological investigations today
(modern age of microbiology).
10. Identify the field of microbiology that studies the role of
microorganisms in the environment.
Introduction to Microbiology
• Branch of biology that deals
with the study of microscopic
forms of life.
• Microbes – short for
microorganisms, single-cell life forms
that can be seen through a
microscope; some are beneficial and
others are harmful
• Anton van Leeuwenhoek
– made the first _____ microscope to
examine the qualities of cloth.
- reported protozoa (1674) &
bacteria (1676)
a. Compound
c. Electron
b. Simple
d. dissecting
Microbes Classification
•
•
Carolus Linnaeus – Taxonomic System, grouping
similar organisms together
2 Types of Cell- Eukaryotes or Prokaryotes
___ unicellular, lack a nucleus (DNA in cytoplasm →nucleoid); bacteria
and archaea
___ cells with nucleus (DNA in nucleus); fungi, algae, protozoa,
• 6 groups:
1. Bacteria
2. Archaea
3. Fungi
4. Protozoa
5. Algae
6. Little animals
• Viruses – smallest microbes, neither eukaryotes nor
prokaryotes; obligate intracellular parasites
Ex: Ebola virus is disastrous in humans, but the virus can be safely
carried by its natural host (bats, monkey, chimp).
Fungi
• Differ from plants b/c they obtain
food from other organisms; differ
from animals b/c they have cell
wall; include:
a.) Molds – multicellular, grow as filaments
(hyphae); reproduce by spores; cottony growth
on cheese, bread, & jams
b.) Yeasts – unicellular, oval; reproduce by
budding
Exercises:
__ molds that produce penicillin
__ yeasts which cause bread to rise and
produce alcohol from sugar
__ yeast infection in female
a. Candida albicans b. Penicillium chrysogenum
c. Saccharomyces cerevisiae d. Escherichia coli
Protozoa
• Single-celled eukaryotes,
unicellular; most capable of
locomotion
• Live freely in water, some
cause disease
• Locomotive structures:
___ – cell extension during it’s
travel; in Amoeba
___ – hair-like projection that beat
rhythmically; in Paramecium
___ – whip-like cell in
Trypanosoma (african sleeping
sickness)
a. cilia b. flagella c. pseudopodia
Algae
• Plant-like eukaryotes;
photosynthesis
• Seaweeds and kelps, large
algae
• Glasslike cell walls
(diatoms) of algae
• Serve as food for marine
animals and make
chemicals used in
microbiological growth
media (solid agar culture)
Bacteria and Archaea
• Single-celled prokaryotes
• Reproduce asexually
• Bacteria - peptidoglycan cell
walls; most are beneficial
• Archaea – cell wall composed
of other polymers
Exercises:
__ What type of microbes is found in extreme
environment (such as acidic hot spring, high
saline lake, or oxygen depleted swamps)?
a. Archaea
b. Bacteria
Viruses
• Acellular, obligatory intracellular
parasites
• Smallest microbes, neither
eukaryotes nor prokaryotes
• composed of small amounts of
genetic material (DNA or RNA)
surrounded by a protein coat.
• Was discovered until the invention of
EM in 1932
Ex: Ebola virus is disastrous in humans,
but the virus can be safely carried by its
natural host (bats, monkey, chimp).
4 Events during the Golden Age of
Microbiology
1. Is spontaneous
generation of microbial
life possible?
2. What causes
fermentation?
3. What causes disease?
4. How can we prevent
infection and disease?
1. Proved that living things
come from other living
things
2. & 3. Microorganisms can
cause fermentation and
disease
4. Certain procedures and
chemicals can prevent and
cure infectious diseases
Is Spontaneous Generation of Microbial
Life Possible?
• John Needham
- boiled beef gravy and infusions of plant
materials in vials, sealed with cork;
revealed life force
• Francesco Redi - in sealed flask,
decaying meat was kept from flies,
maggots never developed
• Lazzaro Spallanzani
- boiled infusion and sealed vials by
melting their necks closed; reported results
that contradicted Needham’s findings
• Louis Pasteur
- father of microbiology; experiments with
swan-necked flask, upright flask, no
microbial growth
Exercises: Which of the above scientists
disproved spontaneous generation?
Pasteur’s Contributions: Father of
Microbiology
• Began the field of industrial microbiology
(biotechnology) – microbes are intentionally used
to manufacture products.
• Discovered that bacteria ferment grape juice to
produce acids; whereas yeast cells ferment grape
juice to produce alcohol
• Pasteurization – use of heat to kill pathogens and
reduce the number of spoilage of microbes in food
and beverages (asepsis).
Buchner’s Experiments
• Demonstrated the presence of enzymes
that promote chemical reactions
• Began the field of biochemistry and the
study of metabolism
Infection and Disease Prevention
• Semmelweis (handwashing), Lister (antisepsis:
phenol), Nightingale (hygiene), and Snow (public
hygiene) investigations laid the foundation of
infection control and epidemiology
• Edward Jenner, showed that vaccination with pus
collected from cowpox lesions prevented
smallpox (field of immunology).
• Later Pasteur, develop vaccines against fowl
cholera, anthrax, and rabies.
• Ehrlich’s search for “magic bullets”, discovered
chemicals effective against syphilis and sleeping
sickness (field of chemotherapy).
Modern Age of Microbiology
• Biochemistry – study of metabolism; practical
applications like design of herbicides and pesticides,
diagnosis of illnesses, treatment of metabolic diseases,
and design of drugs to treat disorders.
• Microbial genetics – study of inheritance in microbes
• Molecular biology – combines aspects of biochemistry,
cell biology, and genetics to explain cell function at the
molecular level
• Genetic engineering (recombinant DNA technology) –
manipulation of genes for practical applications
* Gene therapy – use of recombinant DNA to insert a
missing gene or repair a defective gene in human.
• Environmental microbiology
Environmental Microbiology
• Studies the role microbes play in their
natural environment
- biodegradation
- role in the causation of disease
- control the spread such as sewage
treatment, water purification, and
sanitation measures
Homework
1. Define terms: microbiology, molds, yeast,
protozoa, algae, viruses, biotechnology,
pathogen, microbes, spontaneous
generation, bacteria, archaea, genetic
engineering, and chemotherapy.
2. Why was Pasteur considered as the
Father of Microbiology?
3. Name 3 scientist who disproved
spontaneous generation.
4. Name the contributions of Leewenhoek.