Lectures 2-4,16: Carsten

MICROBES, IMMUNE SYSTEMS AND THEIR INTERACTION

Three Domains of Life

1. Bacteria (prokaryotes)

2. Archaea (prokaryotes)

3. Eukarya (yeasts, fungi, eukaryotes)

Viruses

0.05-1 micrometers

• Bacterial virus ‘bacteriophage’

• e.g. lentivirus, spumavirus

Prokaryotic Microorganisms

0.05-5 micrometers

• Bacteria, Archaea

• e.g. mycobacteria, vibrio

Eukaryotic Microorganisms

5-10 micrometers

• yeasts, fungi, mold, protozoa

• e.g. penicillium fungi

Bacterial Offence

• Competition for nutrients and niches

  • host, bacteria, microbes

• Evolutionary arms raise

  • exchange/acquiry of new genetic material - horizontal gene transfers

Toxins

alter the normal metabolism of host cells with deleterious effects

Bacterial Infections and Intoxication

1. Infection

   1. invasion of intestinal cells

   2. e.g. salmonella, campylobacteria

2. Interaction with host prior to toxic production

   1. adhesion to intestinal cells and production of toxins and effector proteins

   2. e.g. E.coli, V.cholerae

3. Toxin production within host without direct interaction

   1. toxic production in gut

   2. bacillus cereus

4. Intoxication

   1. toxin taken up and produced outside of host in food