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Introduction to BIOL 2421
Course Syllabus
Lecture Meeting Times: TR 12:15 – 2:55 pm
Textbook: Microbiology, An Introduction, 6th edition (with
CD-ROM) by Tortura, Funke, and Case
Lab Manual: Microbiological Applications (Short Version)
by Benson
Grading Procedures/Exams
No Makeup Exams will be given
Attendance
Introduction to Microbiology
Microorganisms are ubiquitous
They are present everywhere in the environment, as well as
in and on our bodies.
Why study them?
Microorganisms can be both beneficial and harmful.
Beneficial examples:
Food preservation, flavor, biogeochemical recycling,
vitamins (enterics)
Harmful examples:
disease, food blights, spoilage
History of Microbiology
FIRST MICROSCOPIC OBSERVATIONS AND CELL THEORY:
1665 - Robert Hooke (England)
described "little boxes" or "cells
beginning of the cell theory of life, i.e. all
living things are composed of cells
1673 - Antoni van Leeuwenhoek (Holland)
1st to observe live microorganisms,
"animalcules"
observed what are now recognized to be
bacteria and protozoa
Spontaneous generation debate:
common belief that organisms arose by spontaneous
generation
certain substances giving rise to specific
types of organisms (flies from manure, toads
from mud, etc.)
1668 (before microscopic observations), Francesco Redi
(Italy) - showed maggots not from decaying meat when no
maggots grew on meat which was sealed in jars
(Opponents - air necessary for life, some
still believed that simple organisms would
arise spontaneously)
Pro: 1745 - John Needham (England)
microbes still grew after heated nutrient
fluids were poured into covered containers
Con: 1765 - Lazzaro Spallanzani (Italy)
proposed that microorganisms came from air
in Needham's samples, found none in broth
after heating in sealed containers
opponents said "vital force" destroyed by
heating and couldn't enter sealed flask
1858 - Rudolf Virchow (Germany)
biogenesis - all cells arise only from
preexisting cells
1861 - Louis Pasteur (France)
heated broth in open flasks with s-shaped
necks -- final blow to spontaneous
generation theory.
The discoveries by Pasteur and others lead to the development of aseptic
technique
the most important techniques that all microbiologists use
methods for preventing contamination by unwanted
microorganisms
Pasteur also introduced Pasteurization
heating which kills pathogens (disease-causing) organisms,
but does not damage the food (milk). 70oC 15 seconds. Is
not sterilization. Used primarily on milk, cream, beer,
wine.
Germ theory and Koch's Postulates:
Pasteur's findings about fermentation by microorganisms
led to the idea that they might be involved in disease. This
is the germ theory of disease.
Ignaz Semmelweis (1840's, Hungary)
showed that simply washing hands by
doctors between obstetrical patients reduced
the incident of childbirth fever
Joseph Lister (1860, England)
applied germ theory to medical procedures,
using phenol (an organic acid) to treat
wounds (found less incident of infections,
many other doctors applied this technique).
Robert Koch (1876, German physician)
First direct proof of bacteria causing disease
Linked bacterium, Bacillus anthracis, to
anthrax.
Developed steps to experimentally
determine if a microorganism is involved in
a disease
1. The same pathogen must be present in
every case of the disease
2. The pathogen must be isolated from the
diseased host and grown in pure culture
3. The pathogen from the pure culture must
vause the disease when it is inoculated
into a healthy, susceptible animal
4. The pathogen must be isolated from the
inoculated animal and must be shown to
be the original organism.
Waging war - advances in combating microbial diseases:
vaccines - 1796 (before Koch) Edward Jenner (British
physician) Developed first vaccine –
Jenner was told by a young milkmaid that she couldn’t get
smallpox because she had already been sick from cowpox
(milder disease) He decided to test her tale… collected
scrapings from cowpox blisters and inoculated a healthy 8yr old volunteer with these scrapings. Scratched arm with
contaminated needle. WHY doesn’t this bright milkmaid
get more credit for her observations?
Origins of immunology - studied since Jenner, use of
body's own defense mechanisms
antimicrobials/antibiotics
"magic bullet" idea, Paul Ehrlich (Germany), early 1900's.
Speculated about a ‘magic bullet’ medicine for particular
diseases that would ‘hunt/kill’ disease organisms without
harming the patient. Tested hundreds of chemical agents
before finding SALVARSAN (arsenic derivative) which
was effective against syphilis
Alexander Fleming (Scotland), 1928,
accidently discovered fungus inhibiting
bacteria – tossed out some cultures that were
contaminated by mold… later on taking a
second look noticed a clear around the mold
where no bacteria were growing. Mold
inhibited bacterial growth. Mold was
Penicillium notatum
Fleming later named the mold’s inhibiting
factor penicillin
Virology
1892, Dmitri Iwanowski speculated about
tobacco mosaic virus. Reported that the
factor causing the disease was so small that
it was not filtered out by filters small enough
to stop all known bacteria. Did NOT
understand the organism as a virus as we
now understand it
1935, Wendel Stanley crystallized TMV,
showed it was different than cellular life.
1940's - electron microscope allowed direct
visualization of virus particles.
Naming and Classification
Binomial nomenclature
System of naming
1735, Carolus Lennaeus, based on latin
consists of: Genus species
Classification
5 Kingdoms: Whittaker
Monera, Protista, Fungi, Plantae, Animalia
3 Domains: 1978, Carl Woese
Eubacteria, Archaea, Eukarya
Main groups of microorganisms:
Prokaryotes – NO NUCLEUS
Bacteria and Archaea
Eukaryotes – Genetic material enclosed in membrane –
nucleus ,Fungi, Protozoa, Algae, Multicellular animal
parasites
Microorganisms
Bacteria – single celled, no nucleus, cell walls contain peptidoglycan
(sugar/amino acid combination) – structural molecule. Reproduce by
binary fission. Derive nutrients from organic materials, which can come
from living or dead organisms. Some make food via photosynthesis;
some can use inorganic compounds as a food source.
Archae- similar to bacterial (no nucleus) cell walls lack peptidoglycan.
Found in extreme environments (Great Salt Lake, Dead Sea, hot
springs, thermal vents)
Three major groups of archae
methanogens – produce methane as a waste product
extreme halophiles – thrive in high salt environments
extreme thermophiles – thrive in hot waters
Fungi – are eukaryoutes. HAVE NUCLEI. Unicellular or multicellular.
Cell wall of chitin. Reproduce sexually or asexually (eg. budding) yeast
is a unicellular fungi larger than bacteria. Other fungi include molds
which form visible mycelia. Obtain nutrients from organic material in
their environment.
Protozoa – unicellular, eukaryotic microbes like Amoeba, Paramecium
etc. Reproduce sexually or asexually, many shapes, some are
parasites, derive nutrients from environment. Many are mobile moving
by pseudopods (flowing), flagella or cilia.
Algae – photosynthetic eukaryotes, many have cell wall made of
cellulose (like plants) present in soil, water (fresh/salt). Unicellular or
multicelluar/colonial.
Viruses – vastly different from other life forms. Contain a core of nucleic
acid (RNA or DNA) – surrounded by protein coat. Must use cellular
machinery of other organisms to reproduce. All are parasites.
Multicellular Animal Parasites – not strictly microorganisms, but are
medically important. Includes flatworms and roundworms.