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Introductory Microbiology
MICRB 201
Why study Microbes?
Syllabus Overview
Who are the Microbes?
(Neisseria gonorrhoeae in human white blood cells.)
Why Study Microbes?
1) Microbes and Man in Sickness
and Health.
2) Major Modern Applications.
3) The Role of Microbes in
Ecosystems.
4) Microbes in Human Civilization.
Why Study Microbes?
1) Microbes and Man in Sickness and Health
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Parasitism; Pathogens (disease causing)
Infectious disease is leading cause of death in developing countries (45%).
Commensalisms; Natural Microbiota (do no harm)
Mutualisms; Natural Microbiota (do us good; probiotics)
2) Major Modern Applications:
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Recombinant DNA technology; cloning; forensics
Industrial Applications (antibiotics; chemical production via fermentation)
Sewage treatment to decompose organic matter
Bioremediation of toxic waste
3) The Role of Microbes in Ecosystems
• Sources for drug discovery (antibiotics & antiviral drugs)
• Cycling of Elements (ecosystem management; global climate change)
• Agriculture (crop diseases; nutrient enhancement)
4) Microbes in Human Civilization:
• Food and Beverage preservation (pre-history)
• Turns in History –
• Moses leads Israelites out of Egypt facilitated by plague (1500 BC).
• Athenians (Greeks) lost Peloponnesian War in 404 BC due to plague
(Yersinia pestis; bacterial disease).
• Fall of Rome (565 AD) due to overcrowding exacerbated by Attila the Hun’s
(barbarians’) army cutting off water supplies to Rome – epidemic malaria (protist
disease) and other infectious diseases.
• Spanish conquering the Aztec civilization (1500’s) by introducing small pox
and measles (viral disease).
• Salem Witch Hunt (1692): Puritan rye gets infected by Ergot (Claviceps
purpurea; fungal plant pathogen); bread makes them loony.
• Great Famine (Ireland 1850’s): potato blight (Phytophthora infestans;
oomycete fungi) starved ten’s of thousands to death; over a million immigrated
to America.
Read the Syllabus!!!!
• Take the lab (MICRB 202)!
• Flow of Topics
• Evaluation
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3 Quizzes/homework (15%)
3 Exams (65 %)
“Bad Bug” Talk (10 %)
Participation (10 %)
• Policies
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Make-up
Requirements
Guidelines
Academic Integrity
Disability Statement
Which are the microorganisms?
• Life forms, or other self replicating
entity, that requires microscopy
technology to be clearly visualized.
• Viruses and all prokaryotic and
many eukaryotic life forms.
• Many are unicellular, sometimes
cells are organized in filaments or
clumps, and others are complex with
only a portion of their life cycle being
microscopic.
• Most can carry out life processes
independently from other cells, others
are highly parasitic.
• They often require specialized
techniques for their study:
microscopy, culturing, biochemical
and molecular.
Note the difference in
scale. The Eukaryotic
cell would be about 50x
bigger than the bacterium
We’ll get back to these
differences in more
detail in a latter lecture.
What are some of the
major groups of
microbes?
Taxonomy of Life:
The classification, or grouping, of organisms based on common characters
used to reflect their evolutionary relatedness. Types of groups, taxa, are
arranged in a hierarchy from the most general (Domain) to most specific.
3 Domains based on
molecular analysis of
ribosomal RNA.
(Carl Woese 1980s)
Two prokaryote domains:
Bacteria and Archaea
A single Eukaryote
domain.
Many Phyla within each
domain.
Difference in taxonomy between us and them.
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Humans
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primata
Family: Hominidae
Group: Homo
Species: sapiens
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Intestinal Bacterium
Domain: Bacteria
(no kingdom)
Phylum: Proteobacteria
Class: γ-proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Escherichia
Species: coli
Binomial nomenclature: Genus species (italic or underlined)
Just like varieties, or races, there are strains of microbial species
(e.g. Escherichia coli K12 versus the pathogenic E. coli O157:H7)
Don’t forget, some animals too!
Flatworms & Roundworms
Trichinella spiralis larva in skeletal muscle (W.M., X260).
The spiral juvenile and its nurse cell are visible in this preparation.
Viruses: An infectious
particle with an acellular
organization of protein and
nucleic acids (RNA or
DNA), and lacking
independent metabolism.
It requires the metabolism
of a host cell in order to
replicate. Viruses are
about 50 to 200 nm in size.
Prion: An infectious aberrant brain protein that causes
abnormal aggregation of similar normal brain proteins; no
nucleic acids. Causes dementia and madness.