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