Micro Lec 5

Question 1

Exotoxins

Answer 1

Produced by gram neg and pos bacteria - Fungi, protozoa and algae. Secreted by living cells. All are proteins and highly specific in their activity. Genes can be found either in chromosome, on plasmids, or on prophages. Most are sensitive to heat. Transported through bloodstream. Can destroy parts of host cells or inhibit metabolic function.

Question 2

Endotoxins

Answer 2

Only found in gram neg bacteria, lipid-protein of LPS (Lipid A) in the OM. Released during bacterial lysis which means antibiotics or host defenses. Release of lipid A stimulates release of high toxic levels of Cytokines and prostaglandins in the host which causes fevers and chills. Heat stable which means it can’t be destroyed by heat. All endotoxins can cause the same symptoms in all people.

Question 3

1st line of defense

Answer 3

Intact skin, Mucous membrane and secretion, normal bacteria. Nonspecific resistance protects against all pathogens which is a natural immunity.

Question 4

2nd line of defense

Answer 4

Inflamtory response, fever, and antimicrobial substances. Nonspecific resistance protects against all pathogens which is a natural immunity.

Question 5

3rd line of defense

Answer 5

B and T cells, Antibodies, specific resistance and acquired immunity.