BIOL 2421 Microbiology Overview Lecture Notes Dr. Weis
Microorganisms:
Most are beneficial:
Environment=> food chain, photosynthesis, digestion, decomposition
Industry=> Chemical synthesis, Food processes, Genetic Engineering
Few are pathogenic
Health and food related diseases
Nomenclature: Genus species
Examples: bacteria, fungus, protozoa, algae, viruses
Current Classification of Organisms:
Three Domains
* Bacteria
* Archaea
* Eukarya
- protists (slime molds, protozoa, alage)
- fungi (yeasts, multicellular molds)
- plants
-animals
Old classification of Prokaryotes and Eukaryotes
Prokaryotes = “pre-nucleus”, genetic material not enclosed in membrane
Eukaryotes = “true nucleus”, genetic material is encloses in a membrane
Domain Archaea
Cell walls that lack peptidoglycan, but are composed of other polymers
No known pathogens; unicellular; asexual reproduction
Environmental groups [usually found in extreme habitats]
a) Methanogens use CH4 for carbon source
b) Halophiles live in highly concentrated salt conditions
c) Thermophiles live in extreme temperatures
Domain Bacteria
Unicellular
Various shapes: rod/bacillus, coccus/spherical, corkscrew/spiral
Cell walls, if present, contain peptidoglycans (carbohydrate + protein complex)
Reproduce primarily by binary fission [asexual reproduction]
Many are beneficial, some are pathogenic
Can be further classified by production of own energy (photosynthetic) vs. acquisition of energy from another source.
Domain Eukarya
A. Fungi
DNA in nuclear membrane
Unicellular (yeasts): oval to round; asexual reproduction (budding)
Multicellular (molds, mushrooms)
Cell walls contain chitin
Typical fungi are molds with mycelia (visible portion) & hyphae filaments
Reproduce asexually and sexually
Absorb nutrients from their environment
B. Protista
1) Protozoa = “first animals”
Unicellular
Lifestyle:
Free living – absorb or ingest nutrients from environment
Parasitic – ingest nutrients from living host
Motility:
Nonmotile
Motile via:
Cilia – short appendages supported by microfilaments
Flagella – long appendages supported by microtubules
Pseudopods – cytoplasmic extensions
Reproduction:
asexual [mitosis or fragmentation]
sexual [meiosis]
2) Algae
Unicellular and multicellular
Photosynthetic, classified based on photosynthetic pigment
Cell wall composed of cellulose
Reproduction: asexual or sexual
Important part of food chain, most are aquatic
C. Plants
Plant Parts (root, stem, flower, leaf)
* medicinal use
* toxic
D. Animals
Multicellular Parasites
1) Worms
a) Platyhelminths
^ Trematodes : flukes
^ Cestodes: tapeworms
b) Helminths
^ Nematodes:
Pinworms, Roundworms, Hookworms, Trichinella
b) Filarids
2) Arthropods
^ Arachnida: Ticks
^ Insecta: flies, mosquitoes, fleas, louse
VIRUSES
Acellular
Nucleic acid (DNA or RNA) surrounded by protein coat
+/- Envelope (a lipid membrane case around whole viral particle)
Inert outside living host
MICROBIOLOGY HISTORY
|
Robert Hooke |
Cell Theory via microscope |
|
Antoni van Leeuwenhoek |
microbe observations with improved
scope and lens |
|
Carolus Linnaeus |
Taxonomic Organism classification (Kingdoms) |
|
Louis Pasteur |
Fermentation, Pasteurization Father of Microbiology |
|
Joseph Lister |
Disinfection of surgical wounds |
|
Robert Koch |
Simple staining techniques Development of solid growth media Aseptic lab techniques Sequence of experimental steps to show that a specific organism causes a specific disease ^ anthrax ^ tuberculosis ^ cholera |
| Walter Reed | Viruses cause disease |
|
Edward Jenner |
Vaccine : cowpox/smallpox Immunology |
| Ignaz Semmelweis | Handwashing to prevent spread of disease |
|
Emil von Behring |
Antitoxin use |
|
Paul Ehrlich |
Discovered agent to treat syphilis Chemotherapy |
|
Alexander Flemming |
Antibiotic (penicillin) |
|
Christian Gram |
Differential staining method |
|
John Snow |
Prevent spread of cholera Father of Epidemiology |
Golden Age of Microbiology [late 19th – early 20th century]
Important Questions/Theories Discussed:
1) Microbial source
~ Cell Theory: all living things are composed of cells
~ Spontaneous Generation: lifeless objects can give rise to living organisms
~Biogenesis: Living
cells can arise only from pre-existing living cells
2) Microbial processes
~ Metabolism
~ Fermentation
3) Disease source
~ Germ Theory of Disease: microorganisms can cause disease
~ Koch’s postulates
4) Disease Prevention
~ Disease Transmission: An infection can pass from one thing to another
Areas of Study: Bacteriology, Mycology, Parasitology, Immunology, Virology
Current Uses for Microbes, primarily bacteria
* Recycling vital elements (CO2, N, S, P, C) between soil and atmosphere
* Sewage Treatment and Cleaning of Environmental Pollutants & Toxic Wastes
* Control of Insect Pests
* Commercial use for food and chemicals
* Genetic Engineering/Biotechnology using recombinant DNA technology
^ Medicine: Gene therapy for D-MD, SCID, CF
^ Agriculture: damage resistant (disease, insect, temp) crops
Microbes in Human Diseases:
I. Normal Flora
* microorganisms on or inside our body
* beneficial
* can cause disease if location or produce virulence factors
* Natural defenses should protect
II. Infectious Diseases
Pathogenic microorganism invades and carries on part of its life cycle and in the process usually causes disease
* Many emerging diseases are due to travel, evolution, and ecological changes
a) West Nile Virus (WNE)
b) Bovine Spongioform Encephalopathy (BSE) [mad cow disease]
c) Ebola hemorrhagic Fever (EHF)
d) Hantavirus pulmonary syndrome
e) HIV-AIDS
f) Swine Flu / Bird flu
g) SARS
h) Monkey Pox
* Old problems reappearing
a) E.coli strains
b) Invasive Group A Streptococcus
c) Inhaled Anthrax
d) Cryptosporidiosis
e) Malaria
f) Tuberculosis