Lecture 3

Question 1

Bacteria

Answer 1

Large, Broad Domain

Question 2

Three forms of relationships with “host” organisms

Answer 2

1. Pathogenic
2. Commensal
3. Symbiotic

Question 3

Pathogenic

Answer 3

1. A relationship between two organisms that is detrimental to one or both organisms
2. Either a strict pathogen or an opportunistic pathogen

Question 4

Strict Pathogen

Answer 4

Ex: Tuberculosis
1. Systemic infection
2. Chronic infection
3. Damage is due to the microphages attempt to digest harmful bacteria; results in the death of good tissue

Question 5

Opportunistic Pathogen

Answer 5

Ex: Staph. Aureus
1. Normally benign; becomes pathogenic if opportunity arises
2. Large wounds = easy access

Question 6

Bacterial Immuno-Evasive Strategies

Answer 6

1. Scavenging Reactive Oxygen Species
2. Synthesizing and placing Protein A on its membrane
3. Producing Penicillinase (antibiotic resistance)

Question 7

Scavenging Reactive Oxygen Species

Answer 7

Stapyloxanthin (evolved in S. Aureus)
1. Golden-colored pigment: interacts with free radicals
2. Strong antioxidant

Question 8

Disabling Antibodies: evolved to produce Protein A

Answer 8

Protein A: binds the Antibody ‘tail’ to render it ineffective

Question 9

Development of Antibiotic Resistance

Answer 9

Penicillin: Staph A evolved to make penicillinase
** no longer used to treat penicillinase**

Question 10

Commensal

Answer 10

A relationship between two organisms that is beneficial or neutral to one and has little or no effect on the other

Question 11

Symbiotic

Answer 11

A relationship between two organisms that is beneficial to both

Question 12

Pro-Bacterial Effectors in the Gut (Benefits of Bacteria)

Answer 12

1. Digestion of Foods
   – complex carbohydrate fermentation
2. Nutrition
   – generate vitamins B and K
3. Trophic Effects
   – influence the growth and differnetaition of intestional epithelial cells and lymphoid tissues
4. Repress Growth of Pathogenic Bacteria
   – competitive exclusion
   – niches in the body
5. Development of Mucosal Immunity

Question 13

Poisons

Answer 13

1. Endotoxins
2. Exotoxins

Question 14

Endotoxins

Answer 14

Surface associated (LPS)

Question 15

Exotoxins

Answer 15

1. Released protein: enzymes
2. Released protein: modify host enzymes
3. Released protein: pore forming
4. Released protein: superantigen

Question 16

Enzymes

Answer 16

Catalyze detrimental reactions

Question 17

Modify Host Enzymes

Answer 17

Alter normal reactions/ activities

Question 18

Pore Forming

Answer 18

Put holes in the plasma membrane

Question 19

Superantigen

Answer 19

Hyperactive the immune system

Question 20

Mithridatism

Answer 20

Protect against a poison by pre-treating with sub-lethal amounts

Question 21

Neutralization

Answer 21

Blocks toxins from entering cells

Question 22

Opsonization

Answer 22

Binding and clustering of antigens to block the activity and facilitate the clearance and destruction of a toxin

Question 23

Active Immunity

Answer 23

Immunize a subject prior to full exposure to poison or toxin

Question 24

Passive Immunity

Answer 24

1. Immunize an animal against the poison or toxin
2. Isolate the antibodies from the animal’s serum
3. Transfer antibodies to the newly afflicted subject