What is Microbiology?
Specialized field of biology that deals with microbes (microorganisms)
usually unable to be viewed with the naked eye
Bacteria Fungi
Protozoa (Protists) AlgaeViruses
Photosynthesis/ Producers
Decomposition
Genetic engineering/ synthesizing drugs, hormones and enzymes
Production of fermented foods such as vinegar, cheese, and bread
Small Organisms with Giant Impact
Knowledge of Microbes allows humans to:
Prevent food spoilage
Diagnose/Treat/Prevent disease occurrence
Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories
Small Organisms with Giant Impact
Virology
tremendous variation
o host cell type
o genetic material
o infection cycle
living or not?
Viruses are obligate
intracellular parasites
A young milkmaid informed the physician Edward Jenner
that she could not get smallpox because she had already been
sick from cowpox
1796: Edward Jenner inoculated a person with cowpox virus
The person was then protected from smallpox
Vaccination is from vacca for cow
The protection is called immunity
History of Immunization
Vaccines have been controversial
Provide an antigenic stimulus that does not cause disease but
can produce long lasting, protective immunity
Small Pox was eradicated by 1980
Bacterial Shapes
Average size: 0.2 -1.0 µm 2 - 8 µm
Basic shapes:
Singular Plural Shape
Coccus (cocci) = spherical
Bacillus (bacilli) = rod-shaped
Spirillum (spirilla) = wavy shaped
Cocci Bacilli (Rod-shaped) Spirilla
Bacterial Cell Envelope
• Part of the Cell Envelope
• External to the Cell Wall/
made of sugars and/or proteins
The Glycocalyx
Two types
1. Capsule - highly organized, tightly attached - thickest
2. Slime layer - loosely organized and attached - thinnest
Functions
1. Attachment – (to other cells and surfaces)
2. Protection
Inhibits killing (phagocytosis) by white blood cells
Resists dessication, viral infection, antibiotic uptake
Cell wall: Gram Positive and Gram Negative Bacteria
Medically Important Biofilms
o Dental plaque
o Infectious kidney stones
o Endocarditis
o Catheters
o Implants
o Cystic Fibrosis
Endospores
Resting, dormant cells
Produced by some Gram+ genera: Clostridium, Bacillus & Sporosarcina
Sporulation -formation of endospores
Germination- return to vegetative growth
Hardiest of all life forms/ withstand extremes in heat, drying, freezing, radiation
Internal Structures
Medical Significance of Endospores
Bacillus anthracis - anthrax
◦ bioterrorism
Clostridium
◦ C. tetani - tetanus
◦ C. botulinum - botulism
◦ C. perfringens - gas gangrene
C. perfringens
C. botulinumC. tetani
B. anthracis
Capsule Stain and Endospore Stain
Protista = Yellow
Protist Diversity
Diatoms
Ulva
